I have fully confirmed that these uBlock Origin static filter rules work with eBay’s guest checkout. For reference, here are all of the static filter rules from this thread I currently use:
*$removeparam=/^mtm_/
*$removeparam=/^utm_/
||ebay.*^$removeparam=~/(_dmd|_nkw|_pgn|_sop|_ssn|action|blrs|cartid|guestCheckoutEligible|ipg|item|itemId|itemid|LH_|sessionid|srt|token|transId|transid)/
||ebay.*^$removeparam=hash