I've also wanted to use the modern widely available dime-o-dozen LCD's with I2C adapter boards. These things are like $6 all day long on Amazon etc.
I've been searching this forum (and others) for a good 5 years or so. I am stunned that there hasn't been some solid examples posted.

My PIC of choice over the last 10 years has been 16F690
Evidently not that popular and it seems to be going on the verge of being obsolete. But they were nice bang-for-the-buck cheap 20 pin processors. About $2 ea
But I do run out of I/) pins because I often use a 4 bit LCD for debugging or for the project itself.

I wish there was some good sample code to get me started.
I tried a few years ago but was at a dead end.

So I will be watching this post and would like to give it a BUMP for more consideration. :-D