Look at it from the other side. Who would want to hire someone remotely and part time so they can learn a new stack? If someone is willing to hire both a part time and remote worker, they will want an experienced dev who can bring value right away.

I learned Django / Python on the job (coming from Perl).

My colleague was always ranting about how much better Python was than Perl. Having inherited her code, I was writing far better code while learning Python than she was after doing a PhD in bioinformatics (~4 years?).