Edit: I’m noting that that 205/45R16 SL does not have adequate load rating for our front axle, which is maybe what you’re referring to (205/50R16 SL should work though, both sizes are technically stretched on an 8” rim (5.5-7.5”). XL rating will not change that.
In any case, either stretch them or get some 7/7.5” rims and run these:
https://www.tirerack.com/tires/tire...ewall=Blackwall&partnum=05WR6DWS06P&tab=Sizes
New pressures will be 35/33psi, or 36/33psi if you decide to keep the 3psi split.
Is there any other particular reason you need XL rated tires? Usually, a particular size is either XL or it’s not at all, primarily in our sizes to keep the max load rating over 1000lbs, which is typically only a problem in very low profile sizes (40 and below, with the occasional 45).
205/45R16 and 205/50R16 are pretty exclusively standard load (SL) rated (don’t forget the R, a dash technically refers to bias/cross ply tires!). In other words, you simply won’t find what you’re looking for. Simply convert load ratings and tire pressure to the new size.
It’s also worth noting that an XL tire requires higher pressures than an SL tire for the same actual load. XL only really exists because the lower profile a tire is, the lower it’s load capacity becomes, and the drive towards “fashionable” low profile tires on modern heavier vehicles necessitated a new standard (aka bandaid approach). XL tires also only have a higher peak load rating because they’re allowed to increase load capacity up to 42psi, where load on SL tires are capped at 36psi for inexplicable reasons, despite the fact that max pressures are much higher than that.
As far as I know, the only deviation from the pattern of sizes in mass market tires is very specific tires - for example the R888R being XL rated for most sizes, and Hoosiers being LL rated for all sizes. Some other tires get designated XL because the particular construction in a size is not adequate without the extra pressure (A052 for example)
Honestly, don’t get hung up on SL vs XL load rating. XL tires with extra plies are generally stiffer, heavier and have worse ride quality. They also are generally designed for the same range of rim widths. As long as you are running appropriate pressure for the load rating, it’s not an issue.
You are also not required to have a certain peak load rating on a car (86, 88, 91, etc), tires are rarely ever specified to run at peak pressure. What you do need is the actual load point and the appropriate pressure for that load.
Use this calculator.
https://tiresize.com/pressure-calculator/