have you made any attempts to contact the issuer? you should try. generally, the extended due date for partnerships was 9/15/2025
you do have the option of filling but omitting the k-1 but then you may want to include form 8275 (not in turbotax which would require you to paper file), this is to provide protection from some penalties if the k-1 is issued and that raises your income tax liability. you probably don't need the 8275 if the k-1 info reduces your liability.
waiting until you get it is a bad idea. you may never get it. sooner or later the IRS is going to send you a notice that it never got that year's return.
