I've already started adapting the Rules Glossary to my 2014 campaign. The players will continue to use their original options, as they're balanced together. My next campaign will be fully 2024, however.
I'm continuing ongoing 2014 games in the system they originated in though I may grab enemies from the new Monster Manual if the mood strikes. After that, I don't know. I haven't started a new game in a while so I'll likely put it to party vote. Leaning toward using A5E as a base with 2014 classes and homebrew options available.
Mostly stick to 2014, but might try out some stuff from 2024 version. Mix and match, depending on level of complexity and power. That's for campaign we currently play.
When i run things, it's 2014, phb only, no feats, with some stuff taken from 5e LoTR. I like to run more grittier games and 2024 just buffs already buffed 5e.
Then you need to broaden your mind That is what we will be doing (mixing both rulesets together), it is very natural to any one who uses house rules. No different really.