Also worth installing a decent SEO plugin, like seopress, rank math or AIOSEO. Not yoast. That way you can manually tweak a lot of seo related stuff to ensure metadata is preserved.

https://www.wpbeginner.com/wp-tutorials/how-to-switch-from-blogger-to-wordpress-without-losing-google-rankings/

I have a 1660 from my old machine and it seems to handle transcoding multiple 4K streams easily. Pretty low power draw as well, I doubt there’s much need for anything more powerful unless your files are in av1 or something.