Before long covid, my goto refuelling snack for 2hour+ interval rides with threshold/VO2 efforts up a few little cat4 hills (263+ feet with average gradient 3%+) was a 250g bag of Tesco jelly babies, that I'd open before leaving, so I could grab some on the go from ~30mins into the ride.
https://www.tesco.com/groceries/en-GB/products/254573427
~60g sugar per 100g and the Tesco ones actually taste really nice to me, plus they're only £1.10 per pack.
Unless I knew I was going to do a sub two hour strictly z1/2, I would usually eat a banana with a glass of water ~30mins before heading off.
Another favourite pre-ride snack was a sandwich, that could have any combo or all of...
Banana
Peanut butter (no palm oil)
Jam/marmalade
Marmite
Cheese
I was very late on the bandwagon to discover bidon mixes that include sugar and caffeine, for a long time I just used one hydration tablet per 700ml bidon, but for the last ~12 months (mainly for Zwift races) I now have this big tub on S&S...
https://www.amazon.co.uk/dp/B008KZ9OGI