Comment by fensgrim

I'd go for a "real device cloud", AWS/testgrid/browserstack/whatever.

However depending on your users' demographics, it might be a good idea to take a look at https://dontkillmyapp.com/ and get few used devices from huawei/xiaomi to run local tests as well, generally the farm experience wouldn't exactly match local experience (e.g. what happens when you leave the device without usb connection running overnight, what happens when you leave device unattended for a week). US/Europe? Don't bother. EMEA? Maybe get a couple devices running lineageos/grapheneos/calyx as well. China? There's https://www.alibabacloud.com/help/en/mobile-testing but it wouldn't match real user experience due to how dpi/GFW is set up.

Also check out https://developer.samsung.com/remote-test-lab and https://developer.huawei.com/consumer/en/digix-lab/ if you want to save some bucks on renting stuff.