My play for quite some time now has been Google Voice with a cheap SIM with data and voice for my travels in the UK and Europe. When cell service is poor, wifi is available in many restaurants, pubs, and accommodations so even without a local SIM, I can make calls. I haven't had a problem with Google Voice so long as I have a reliable wifi connection--and I was originally a Hangouts user. For GPS on the road, the data from the SIM is great, and occasionally, I find the SIM call quality better than wifi connections. I have a PAYG SIM through giffgaff that works well for my needs, including in Ireland, France, Austria, and Italy, but depending on where the majority of your travels are, you might find another service more reliable or cheaper or both.

Bottom line, though, is that Google Voice does everything for me that Hangouts used to. And this combination has worked so well, I haven't felt the need to move to Google Fi--although I probably would if I took, under non-covid-19 circumstances, more than three or four trips to the UK/EU each year.