Renewal is all that matters.

Namecheap is $14.95 renewal for me (I believe this is slightly discounted due to how many domains I have)

Porkbun is $11.06

That may not seem like much but it’s a couple hundred dollars a year difference for me (some TLDs have a bigger spread).

Visited Namecheap and currently registration is $10 (normal being $15) and renewal is $17 (wtf). The $6.5 is a promotional offer for one single registration. Porkbun is $11 all. So, yes, you get first year cheaper, but by third year Porkbun will be 3/4 the costs.

which part of "cheaper on renewals" do you not get