This is true but for some people the balance aspect probably limits the weight they can push in the single leg exercises. But I’ve been doing bulgarians with 75lb dumbbells and I almost certainly couldn’t do 300lbs on a back squat at the moment.
For OP, your options are to 1) use straps or 2) do single leg leg press where grip isn’t an issue. I think I prefer option 1 just because the balance and control is good practice. But for pure cycling carryover the leg press is a good option too.