Sorry to hear this.
As I've see it so many times and quite a few YouTube tutorials (although a blessing to have) miss this step out (yes, GMBN have missed it too) it's VITAL to the bleeding process.
BEFORE pushing the pistons in, they need to be cleaned (isopropyl alcohol) throughly.
If, you pushed your pistons into the caliper body, without a proper clean, then you have just pushed gunk into the caliper body through to the hydraulic fluid and onto the inside of the piston seals. Thus reducing their ability to freely move in and out, aka, "sticky pistons"
Hopfuly as the simpler fix to opening up the caliper body, you can leaver out one piston at a time (while holding the other/s back) but not too far that it pops out. Clean it well then push back in. Repeat a few times or until fully clean before moving onto the next one. You can usually leaver a piston out 9 - 12 mm but again - be careful. Set a, DIY 'block' in place so you don't have to worry, just leaver out until it gets to your block.