I find Parallels in general faster than VMFusion at the minute. You can see a comparison
on my channel here. I just found the overall performance of the 2018 woeful in pretty much everything tbh. I'm a bit spoilt for choice on machines however so I'm sure there's an element of that. To be fair I also
like my i7 Macbook! A lot of it is down to expectations. I only expect my Macbook to run mail and web-browsing, I expected a bit more of the Air, and just didn't get it.
Review of the air here on my channel by the way. (Sorry, feel like I'm pimping my channel, I'm not - I genuinely think there's stuff in there you'll find useful).
Look at the benchmarks however:
https://www.dropbox.com/s/kyhq9ingwpye85r/Screenshot 2020-05-08 at 12.36.36.png?dl=0
The 2020 Air has a 1030NG7 i5 in it, which Geekbench 4's at about 5233 single core, and multi-core 13694. It's a lot more capable than the 2018. A LOT.
My i7 2012 Macbook by comparison is single core 3796, multi-core 6962. There's no way I'd use the 12 for Virtual machines, it's just way too frustrating.
The 2016 unit, assuming you have the m7, is 3591 single, 7035 multi. That's not far off the 2018 Air - the 2020 Air is a lot quicker.
The base model 13 Pro i5 is 4610/16880.
For virtual machines I'd be going for the 13" base MBP tbh if I could. I know benchmarks aren't everything, however they're a decent indicator for overall general performance.