Out of curiosity, do you play in-person or on a VTT?It doesn't seem particularly hard to me, though I don't have to worry about player buy-in. We play with our homebrew version of core 5e and will continue to do so going forward. I have not needed WotC since the core books were released. Now I treat them as any other 5e publisher. If they make something I like I pick it up and incorporate parts into our game.
So I guess my answer would be: stick with what you have and add bits from other publishers that you like.
In-person it gets extremely easy to just use whatever you like because you just roll dice and go. Want a character option? Just find a spot on a sheet and write it down. There isn't a spot? Make a custom character sheet to create a spot. Thinking back to different TTRPG I played in the 90s, we tended to just mash together whatever and frequently ended up with custom character sheets that supported our play style.
I think for VTT play, you either have to be willing to spend a bunch of money, spend a lot of time manually creating things, or lower your expectations for what the VTT is going to handle. I've only ever used Foundry and Roll20 and IME, Foundry has more room for customization but the learning curve to doing that customization can be steep. If you're using a mashup of different 5e products, it might just be best to go with the simplest VTT possible and just have something to display a map and tokens with.