If you're going to buy any Avira software, Avira Prime is the one to get, as it includes every free and paid tool from Avira. However, even with its entire posse of apps it can't top the best cross-platform multi-device security suites.
Avira Internet Security upgrades some components of Avira Free Security to their Pro equivalents, but others still require separate purchase, and many typical suite components are absent. It’s just not a big improvement over the free suite.
Avira Antivirus Pro offers the same basic protection as Avira Free Security, plus a few added features that don't all work well. Stick with the free edition or, in a business setting, make a better and less expensive choice.
Another antivirus is getting in on the crypto hype. This time, it’s Avira. The antivirus just happens to be owned by the same company as Norton 360, which is also offering a crypto miner.