The idea is to use the bow to crit fish for eldritch smites, otherwise yeah, eldritch blast eventually outpaces the pact weapon every time.
You sure?
Level 13, half-elf Shadow of moil for advantage.
18 Cha, crossbow expertise, sharpshooter, elven accuracy, thirsting blade, life drinker, and improved pact weapon, starting fight 1 for archery style.
3d6+12Cha+3 improved pact weapon + 30 sharp shooter = 55.5
60% with Cha +5% improved pact weapon + 10% archery style - 25% sharpshooter * advantage =
50% * tripple advantage = 87.5%
= 48.5625 DPR.
Level 13 half-elf, Shadow of moil for advantage.
20 Cha, elven accuracy, agonizing blast. Shadow of moil for advantage.
3d10+15 =31.5
65% cha * tripple advantage = 95.7125%
= 30.1494375 DPR.
Hexarcher does 62% more damage, ignores cover, can shoot in melee, and has an extra 20' range, Con saves, and 21.5 more HP (including second wind).
Though at the cost of a feat, 2 invocations, 2 AC (EB can hold a shield), and a level 7 spell.
That's a heavy trade off for heavy damage, but i'd say hexarcher wins.
Level 18 hexarcher, with foresight and elemental weapon.
3d6+15Cha+3 improved pact weapon + 30sharp shooter +3d4 EW= 66
65% cha + 5% imrpoved +10% archery +10% EW - 25% = 65% (same as EB)
= 63.17025 DPR.
Level 18 EB, with foresight and hex.
4d10+20+4d6 =56 * 95.7125%
= 53.599 damage
Hexarcher still does 17% more damage. Though the cost went up, to include another feat and more spell slots (since hex last 24 hours).
I'd put EB as the victor here. Too much cost for hexarcher. Though it's fun to see that you could completly make up the -5 to-hit.