I have been using Big Sur since the public release on my base 2020 i3 MBA. No issues. Smooth as butter. Op has a 2020 i5 MBA. It shouldn't be a problem.
MacRumors is kind of an echo chamber of the good and bad that is Apple. Everyone is jumping on the M1 bandwagon, and it does look like promising and exciting step forward. But, there are posts recommending that folks with perfectly functional early model 2020 MBAs trade-in for the M1 MBAs. That seems a bit rash to me. If your computer is doing everything you need and is performing well, take a breath and wait a few beats to see what happens. My guess is there will be some growing pains. Also, It probably won't be long and you will see rumors about a new form factor for the MBA with an edge to edge screen, better camera, and a next generation M processor. Perhaps even better battery life so they can reduce the size and weight of the chassis and battery.
Remember when the 16in MBP came out and everyone jumped on that band wagon. Remember when the early 2020 MBAs came out with scissor switches and i5/i7 processors and everyone hailed those computers. With time, they all show some warts because nothing is perfect.
You know what, I agree with this.
I bought an early 2020 base MBA. This laptop does everything I want, very fast, and has a very good battery life(I stay at my desk all the time anyway). Now that m1 MBA is out, I wish I had bought it instead, because its faster at tasks I never do, and has 3-4 hrs extra battery life, over the ~9hr I already get.
I thought about selling it for $600, and getting a new one for $900. But then I thought, I'm just taking a $300 hit, for a marginally better laptop(for my use case), when I'm probably gonna get a new Mac 4 years down the line anyway, regardless of what I use now. There's always going to be something better around the corner, and although if I had bought a laptop 6months later, I would have definitely go the m1 one, its okay. My current notebook, works very well anyway. Maybe the m1 model will show some problems couple of months down the line, maybe there's a gamechanging re design 2 years down the line. The next laptop I buy after 4 years, will be much better than both.
So I'm gonna chill with my current laptop, it works great, and be happy Apple is doing well, because my next laptop will be a Apple laptop anyway. Its kinda cool I have the last Intel Mac.