+1 on the Ooma.
I have the same setup as above. I wanted a phone nearby in each part of my home in case of an emergency. So far that has happened only once. It is worth the $60+ dollars a year to know that I can crawl to a phone if I have to.
Another option is Google Home mini. You can get one for about $30 and then say "call xyz" where xyz is one of your contacts - the microphone has a range of about 30 feet. You only have the one time cost plus you get all the features of a smart speaker.