if you have a minecraft.net account. Go to "my games" and then click on "change skin". From there scroll down until you find "change your cape pc-mac". your cape should be there.
Ever since they used LWJGL library 3.3.1 for the more recent snap shots and versions (in this case 1.19) this problem happens.
so far I have dealt with this bug since snapshot 22w16a and beyond.