Change YouTube embed widths with new WP?

Hi, I noticed this option no longer works:

https://www.wpbeginner.com/wp-themes/how-to-set-oembed-max-width-in-wordpress-3-5-with-content_width/

Any suggestions for how else to change the embed width? I have quite a few videos so a manual option may be tough to implement. There is an example below. Thanks ahead of time for any possible help.

https://www.rdlfitness.com/walk-with-heavy-weight/