well. Nvidia bins there Turing chips in two categories:
TU104-400-A1 are Normal Chips (no factory OC permitted).
TU104-400A-A1 are Binned Chips (factory OC permitted).
Both support manual overclocking, but the 400A will be "better quality" chips which will allow higher overclocks. If you buy a factory overclocked model from ASUS or any other board manufacturer you will have for sure a "A" version of the chip, which will allow for higher overclocks than a non-A version. If you buy a reference model from ASUS without factory overclock you will might have a "A" version of the chip, but it is not guaranteed.
But even if you get an "A"-binned chip the silicone lottery is still in play when it comes to the actual overclocking limit. How high you can overclock your chip is a combination out of chip quality (silicone lottery and A or non-A chip), quality of cooling, and power limit. Cards with higher power and better cooling will potentially better overclock.
Just to give you an idea. My card, the MSI 2080 Duke, come with an "A" chip and an factory overclock at 1845Mhz. If I don't overclock the card it runs in games with around 1890Mhz GPU clock. I manually overclocked it without touching the fan curve to 1910Mhz and now it runs in most games with 1965Mhz.
If you don't want to manually overclock, you can go with any factory overclocked model that has a good review in terms of sound and temps. If you always and only play with headphones, this might not be important for you.
By the way, overclocking of video cards is pretty easy and very safe and should be done. But it is not necessary to push it to the extreme. You can run an automatic overclock on RTX cards with the OC scanner (from Nvidia) which is part of the MSI Afterburner or EVGA Precission X1 tool. This takes 20 minutes, requires not skill and is save and will give you a decent overclock that is specific to the quality of your Turing chip.
For me personally I always go with a card that is factory overclocked and has good reviews in regards to temps and noise. Than I usually overclock it manually (or with the OC scanner tool) as high as I can go without increasing the fan curves (and noise).