A small addition to this post - my equipment list and impressions.
Bags:
I had 2 panniers, 1 huge saddle bag, a frame bag, a snack bag and a handlebar bag.
Panniers are great, nothing to change there. Same with handlebar bag and snack bag. The saddle bag was just stupid. I had to fit somewhere a yoga mat that I took in addition to the thermarest. I first put it on the rear rack, beneath the saddle bag, but it barely fit there and kept popping out, so I tied it with bungees on top of the saddle bag, and for that I made it lie flat on the rear rack. Effectively, it was no longer a saddle bag. It would have been so much better to have a proper backpack instead. I even have the perfect backpack for that: it's large, convenient and waterproof. I can carry it with me as carry-on luggage, conveniently. Also, Kona Sutra has a front rack. So next time the setup will be: 4 panniers, handlebar bag, snack bag, backpack on the rear rack, and that's it.
Camping equipment:
The tent I borrowed from a friend is Nordisk oppland 3 lw, and it's just amazing. It's incredibly light and compact for its size, and the size is absolutely huge - it has plenty of space in the inner tent and then another huge space as an anteroom, good to fit all of our equipment. I absolutely love this tent. However, while extremely light
for its size, it's pretty heavy and bulky in absolute terms. If I only bring a tent as a backup, as I might do next time, perhaps I'll bring my Nemo Hornet 2. It's way smaller but, well, way lighter too.
The pad - I mean, thermarest is great, and put on top of a yoga mat, provided me with perfect support, orthopedic matress style. I might reconsider the yoga mat though. I mean, it's cheap, I can use it to pad the bike in transit, then tie it on top and not care too much about it. The jury's still out on this.
The sleeping bag - mine is pretty old, a Lamina 35. It's bulky, and the rating is just way too low - I don't need this for trips like the one we had, especially with liner added. I'll have to invest in a new one.
The liner is great. Also, I brought along a footprint for the tent, and it's just sensical to use it, to avoid damaging expensive equipment.
The chair. I loved the chair. We put it in the anteroom of the tent, you could actually sit there, and do stuff: organize your kit, read, have a cup of tea. I mean, it's a luxury, but I loved it.
The pillow. I bought it for peanuts on Ali, and it's pretty great. Wouldn't give up on it for the world.
The mosquitos net. Absolutely useless on this trip, but I might take it if/when I ride in Finland (the mosquitos there are brutal).
The USB-rechargeable head torch, the camping towel - all good.
Bike stuff
Spare chain - stupid, didn't need it. Might take a few more magic links next time.
Spare tire - didn't need it. Probably won't take with me next time - especially if I go tubes. 2 tubes - yes, that I'll take.
A nice floor mini-pump off Ali - excellent product, will use it from now on.
Lock - yes
Lube - yes
Sealant - stupid, didn't need it for a trip this long
Multitool and Leatherman - yes and yes
Lights - of course. And these are pretty great ones. The front one is a brute, its battery holds forever and it's very strong. Guess where I bought them.
A bunch of straps, bungee, zip ties, electrical tape, some inner cores - yes, by all means.
Puncture kits - didn't need them, will obviously continue bringing them
A microfiver rug for the chain - yes
A combination lock and chain - yes, pretty useful for leaving the bike near shops for short durations
Cooking
Jetboiler - yes, loved it. So yes, you need to buy a gas cartridge. Not a problem if you're approaching it purposefully.
A knock-off mini-airpress - loved it, will use again.
Collapsible bowls, kitchen set off REI, a refillable set for 4 condiments, a container for sugar, tea bags and one spare one - all were used, all were great.
Clothes
A running rain jacket - I used it a lot. We were lucky with the weather, but if there'd have been a serious rain, I'd be drenched in it. I'll need to fix my Arcteryx Alpha SV and bring it along. It's quite bulky, but it's called a rain fortress for a reason.
A puffy jacket - didn't use it at all, except gave it to Daniel after he lost his fleece jacket. Still, a good thing to have.
Spare pants - too heavy, should just bring 2 pairs of the light
Decathlon pants - I only had 1 pair, and I basically wore it for 10 days straight.
Padded short - I brought 1, needed to bring 2.
T-shirts - I had 4, 1 of those - long sleeve, seemed about right.
Middle layer - forgot to pack it eventually, but did ok without it, probably redundant.
Underwear - I had 4, and it was about right.
Socks - I had 2 pairs of running socks and 2 pairs of long socks, ended up using 1 pair of running socks a couple of times and 1 pair of long socks - 1 time.
Shoes - I wore sandals throughout. Brought with me running shoes too, and that's fine, even though I didn't use them during the trip (but we did go running once in Belgrade).
Base layer - completely redundant on such a trip.
Misc
Medicines - I went a bit overboard there, will need to cull a bit more carefully next time. I also brought a blood pressure cuff, which was just silly. However, If I mostly use hotels next time, I'm going to bring my CPAP with me, for sure.
Camera - haven't used it once, dead weight.
Bikeline books - rule
Power banks - the 30,000 is just too heavy. The 10,000 is great, I just need another one just like this one, and I'm set.
Tablet - I ended up bringing my laptop, which turned out to be a good choice. For that reason I also brought a slightly bulkier charger, which was ok.