Your concerns about the 2022 Newmar Bay Star 3609 are valid - steering play combined with uneven right front tire wear at only 11k miles suggests issues beyond normal F-53 characteristics, even with Liquid Springs and Safe T Plus installed.
Off-center steering wheel fixed by adjusting tie rods equally both sides. Return to alignment shop if recently done - they should fix free.
To find the correct drag link boot for your 2015 Freightliner XCS chassis, you'll need the chassis VIN and specific Freightliner part numbers. Contact Freightliner dealers or use online parts catalogs with your chassis specifications.
The 2009 Motorcraft MDOE35 drag link likely won't fit your 1999 F53 due to significant chassis changes in 2009. Check Ford commercial parts dealers or cross-reference with ES3466R for proper fitment on pre-2009 F53 motorhomes.