Agreed. Full-length mirrors are clutch for learning how to squat and deadlift by yourself. Not having them removes certain visual cues that can warn you that you're on the train to Snap City.
I'd be posting form checks either way (home gym or gym gym) until it is assumed you know what you're doing. The deadlift has a reputation for permanently fukking people all the way up even though it's the easiest barbell lift to bail out of (tied with rows).
Also, a gym would have more equipment for strengthening the muscles used in deadlifting: lat pulldown stations, leg curl machines, Roman chairs, hyperextension benches, etc.
Not necessarily a bad idea but none of those things are the same. If anything squatting will strengthen bro's muscles needed to dead.
A squat is a lower-body push and a deadlift is a hip-hinge/lower-body pull. On a deadlift you push the floor away with your feet as you bring the weight up. A squat is a controlled descent and climb out. A lot of muscles are used in both. Some folks are back and trap dominant deadlifters, some are hamstring dominant. Your back is used when pulling from the floor, but dude shouldn't be putting his back into it, if that makes any sense.
Your back doesn't work when you squat? Only somebody that's never squatted heavy would say so. Your quads don't put in work during deads? Almost all the same major muscle groups, just a different movement pattern. My dead always goes up even without pulling just by getting my squat stronger.