Anyone else?

Yup, I do.

I have one unit that stuck on low levels that is LA!Lyn from LB, but i usually lvl up most of 5* just incase, even if i'm not planing to use them.
But i have a lot more 5* copys that i don't want to use because of ivs, or beeing lazy to upgrade iv's of copy that i'm currently using.

Well, more like units I use a little bit and then kinda don't anymore.

I summon for new units a lot more that for getting merges. Which has the result of a large collection of 5*, but only two above 5* (Sigurd and Hawkeye)

I try and level all of my unique 5-Stars to max rather than keep them at Level 1 with no SP and EXP.

I hope to one day be able to give them functioning builds--even the bad IV ones--, but that depends on what fodder I have available / am willing to use. Merge projects still come first, and I prioritize favorites over any 5-Star, but I get a lot of fun out of building all sorts of units so I don't mind giving some investment to my lesser-used 5-Stars.

Yup I only need 50 more 5 so I’m going to be choosing wisely

Pretty sure everyone who has played for a while has more 5* than they can realistically use. I still level up one copy of every 5* that I get.