We’d actually reccomend another strategy.
Just pass the SF id for the related record in your URL. This simplifies the URL string and avoids the URL encoding issues.
Then on your New Record page - create another model that uses the Id parameter to retrieve data from the existing record. This data will include name, but can include whatever else you want.
Then your “new record” models will use “Field from another model” conditions to pre-populate data instead of using URL parameter conditions.
Then you should get the name you are interested in.
