Everyone had different potion drinking rules, which was a big laugh for everyone really. Some could drink it as a bonus action (D&D 2024), some only as an action (D&D 2014), and some with a bonus action because of some ability they had (A5e).
You used spells from your book so a fireball for the A5e wizard was 25% worse than the fireball the D&D 2024 light cleric had. The A5e wizard ended up getting a special version of fireball that was 1d6 higher, though.
Playing with a mix of 5es at one table can work. But I don't recommend it.
I think it works better to pick one core book and core set of rules for everyone and then modify stuff from the other 5es if you want to use them. Tell players that if they pick stuff outside that ruleset, you guys will have to work together to smooth out the rough edges (which you should probably do anyway -- none of these rulesets are ideal).
A lot of stuff from other 5es (luck and doom from TOV, safe havens and supply from A5e, better exhaustion rules from D&D 2024) can be used across 5e systems but having a core understanding of the rules and then modifying those rules to suit your table is probably better than the "Everyone has their own instance of the rules" approach I did.
Still, we ran the campaign all the way to 20th level and all of us totally enjoyed it.