If the person(s) sending you photos have turned on a feature to send photos at a reduced resolution there isn't much you can do with any app. Make sure RCS chats is turned on on your phone and also the person(s) sending you the photo.
There are other texting apps but I think the only one that supports RCS chats is Google messages, Verizon Message+ and Samsung messages both used to but both have dropped those apps. I tried Textra and Chomp last year but those are SMS only. Never tried WhatsApp but that is another one.
