You know you could literally google HoF QBs drafted per round and find the data you are looking for.
https://www.profootballhof.com/heroes-of-the-game/hall-of-famers-by-draft-round/
The quick answer is the majority of them are first rounders.
1st round - 14
2nd round - 3
3rd round - 3
4th round - 2 but none in SB era
5th round - 1 but none in SB era
6th round - none
7th round - none
Later rounds and Free Agents have none in SB era except for Warren Moon. Although this looks to be up to 2016 as Kurt Warner made it and Romo may make it. Brady will be the 1st 6th rounder to make it. Wilson will probably make it as a 3rd rounder. Brees as a 2nd rounder. In terms of 1st rounders, there will probably be about another 6-10 added from the Mannings, Mahomes, Rivers, Ryan, Rodgers, Jackson, Watson, Wentz, Newton, Big Ben, Flacco, Luck. Not saying all those guys make it but combined they are more 1st round QBs that will make it than all the other rounds combined.