My spouse and I had to file a paper return again this year because we did not receive my spouses’ IP PIN, we have since received it. Can we amend the return and e-file?

That is unwise to switch to efiling (NOT AMENDING)  when you have already mailed in a return as this can cause further delays in the processing of the return. 

NO.    If you already filed a return then you should not file again unless you want to confuse things and delay your refund.  You do not want two 2020 tax returns in the system at the same time.   Sorry---mailed returns do take longer, but now that you mailed a return you need to wait it out.   And.... receiving that PIN is not a reason to "amend" your tax return.   You only use the amendment process for a return that has been filed and fully processed.   When you really amend you use a special form called a 1040X-----and it is currently taking the IRS at least six months to process amended returns.   That would not be an effective  or correct way to resolve your issue.