I would say don't stress about running out of charge (as long as you don't leave it for 6 months without a charge, which if you're using to top up before rides, you won't). It does 4 tyres from flat. If you use inner tubes you'd probably be well out of tubes and emergency patches by this point. If you run tubeless, you're probably not reinflating from flat. I've started carrying a tiny USB C to USB C cable in my saddlebag, with which I can use the reverse charge from my phone to top the pump up, my Garmin, lights, even my Di2 using a tiny little adaptor you can get from AliExpress (in emergencies - I don't make a habit of it...). And all of this is a massive upgrade from the Co2 cartridges many of us took out for years before.
BTW with regards to the suggestion to using the car sized pump, I've got one of those too, and it does work, but I found the cut off was nowhere near as precise at normal road bike pressures. Generally I'd end up with tyres 5 psi higher than I wanted. Could be just my particular 'car pump' but the Cyclami one gets it spot on every time.