I just came across this as I was trying to figure out a better way to ensure matching for things and with the new agents, you can use the IMDB/TVDB ID as part of the name to ensure it matches right.
With advanced on in both Radarr/Sonarr:
Radarr Movie Name:
{Movie Title} ({Release Year}) {imdb-{ImdbId}}
Sonarr Series Name:
{Series TitleYear} {tvdb-{TvdbId}}
And for consistency, I made the Standard / Daily names with the year as well:
{Series TitleYear} - S{season:00}E{episode:00}
{Series TitleYear} - {Air-Date}
That should make matching perfect on the new agents as I was using Plex Autoscan to fix things but if I can remove piece to simplify things, I'm always down for that.
Plex Articles:
Naming and organizing your Movie files | Plex Support
Naming and Organizing Your TV Show Files | Plex Support
Slight update, if you want to remove some odd characters, you can use Clean before all the items so CleanTitle or CleanTitleYear.
Once that change is made, you can follow two steps to rename everything to match, this will take some time to do and cause things to be re-analyzed by Plex so be mindful.
In Radarr/Sonarr, you can use the mass editor/series editor, select all or one to test with, change the root folder to existing one you already have and pick yes to move the files. This will automatically rename the root folder. Next, you can select all or one to test with and rename the files inside the folder so it's a two step process to fix the folder and then the actual file name.
I redid my library and finished up in about 4-6 hours for my Movies and maybe 18-24 for my TV shows as many more episodes and those just take longer. So be mindful, plan or split up into manageable parts.