Thanks for the advice, Nick. I ordered the kit. I'll check with my mechanic to see if he thinks resurfacing will be required. I see that having a flat surface is critical for the seal.

I'm going to go with this high-temp thread locker adhesive for the Time Sert. I saw some videos that don't use one, but it seems like it will be more secure with it.

Loctite Threadlocker Red 271

https://www.amazon.com/Loctite-Threa.../dp/B000FP8EUS

Also saw this one, but it has much fewer reviews:

Tekbond 120 threadlocker adhesive:

https://www.amazon.com/dp/B092JPPFG7/

I've ordered this replacement drain plug with magnet:

https://www.amazon.com/gp/product/B086RQZYZM/

I'll use the copper crush washer like the guy with the N62 550i in the reviews:

...the length of the threaded part is the exact same as OEM.

I did not use the included washer but instead opted to use the copper crush washer that comes with a new Hengst oil filter. It’s thinner and more pliable than the included aluminum washer, leading me to believe it will create a better seal...

As he notes in his review, pretty expensive for a oil drain plug. On the other hand, it's steel, has a good magnet and is made in the USA.

Edit: It is nice that the lower pan can be replaced, but I think the risk with a used pan, plus the ongoing concern with the aluminum threads make the Time Sert the better option.