I've found that the best way to get through it is to move through that range of motion more often, unloaded. Stretch, do a handful of air squats, then do them again later, then again later. Not saying you have to work out, but moving thorough it and exposure will help.
Edit: also drinking lots of water will help.
Are you sleeping enough?
Would like to add, are you also eating enough?
I mean I get about 6-7hrs daily. My work schedule makes things hard, and then with overtime being unpredictable it's hard
That's understandable. DOMs from training legs definitely kicked my ass when starting out, but I gradually acclimated.
How many sessions have lead to 5+ days of this for you so far?
The first leg I've done in 7 years was friday. Before that I was just running 4 days a week(easy run, tempo, interval, and long run). I have huge legs but trying these different compound movements makes me realize how weak I am
But before that I've done leg press and calf raises and the like, some stationary bike. Free weight with barbells really scared me because I don't want to mess up my back with bad form. Like it scared me to the point that I'd get under the bar and I start shaking because I don't want to mess up. But now I can under there and do it, it's just my legs are really tight and it gets hard getting down into a low squat
If that was your first leg day with barbell back squat, I think 5ish days is understandable.
First time hits different but subsequent sessions will not put you out that long if you keep up with it.