alternative for Google txt messages app?

I wouldn't really say there are many alternatives.

RCS is a huge thing for texting, which is mostly only available in google messages

I still have the Samsung messages app on my S22ultra, i prefer it not like the naff Google messages app. Google will always spy on you.

Find Google fine for me, simple enough, I don't use RCS

Hi @MrSylv If you are not too concerned about RCS some rate Fossify https://www.fossify.org/apps/messages/

Limited options otherwise unless you wish to use instant Messaging apps which I use more than SMS. https://eu.community.samsung.com/t5/samsung-lounge/analysis-of-best-messaging-apps-for-security-and-privacy/td-p/14084739

In the Uk you should still be able to use Samsung Messages. I still use it on my S26 ultra with ONE UI 9

Check in Samsung store
https://apps.samsung.com/appquery/appDetail.as?appId=com.samsung.android.messaging&cId=000008843339