I have never had a problem before (Pixel 6a), You are probably getting the popup because you need to install it via downloading and installing the apk file (known as sideloading). Usually, by default, phones won't let you do this as it can be a vector for malware. You need to manually enable it. Your version of Android might have it in a different place than mine, but to enable sideloading on my phone, I had to go to Settings -> Apps -> Special App Acess -> Install Unnown Apps and make sure that Chrome is enabled on that list (files might be needed as well).