Su57 in Algeria is unrealistic, it's just speculation. The two counties have a real cold relationship for the last 2 years and I don't see them going ahead with this sale now of all times. It's a plane that is not fully ready, it's not being produced in large quantities, and Russia has closer allies to sell this to once it's ready rather than Algeria. In 10 years or so I don't doubt it will be in the Algerian dotation, unless they collapse before then. Russia can't even sell them spare parts for their current fleet let alone a whole new plane
As for us, the F35 isn't a plane made and designed for us. It's for super close NATo allies and it's being used almost as an extension of the US Air Force in other countries. It relies on a maintenance scheduling that is time sensitive, primarily driven by just in time deliveries making it's operational availability poor, and even more so its key software has to run on US servers etc. it's not a realistic option for us regardless of how much trump wants to sell it, if the UAE can't get it despite being ready to throw billions then we won't either.
Realistically we are likely moving towards two additional vectors. A high tech one in small quantities for the 2030s to counter anything Algeria might buy in the next years and I have no doubt it will be a Rafale (unless trump forces us to get the f-15ex but honestly I lean more towards rafale). Then a second vector to be the second backbone of our fleet and replace the aging old planes; for this one I see us going with more cost effective options or something with local assembly; Locally assembled JF17 would make sense as it's consistent with the visits and the size of the need of 48 or so vectors but it's a half measure in my opinion. The other option would be J10c maybe with a local assembly component which would be my preference as it's miles better than jf17