Noticing how the cult scout/armoured sentinel datasheet in Codex:GSC is a different datasheet from the scout/armoured sentinel datasheet in Codex:Astra Militarum, the following list came to my mind ...
okay, to be honest, I though about running a bunch of sentinels with missile launchers and hunter killer missiles (HKMs), but after fiddling around and noticing what I could take instead of the HKMs, I arrived at the following list:
Genestealer cult (outrider detachment)
HQ
Jackal Alphus 70
Fast Attack
3x Cult Scout Sentinel, multilaser 105
3x Cult Scout Sentinel, multilaser 105
3x Cult Scout Sentinel, multilaser 105
3x Cult Armoured Sentinel, plasmacannon 120
3x Cult Armoured Sentinel, plasmacannon 120
3x Cult Armoured Sentinel, plasmacannon 120
Heavy Support
3x Brood Brother Heavy Weapons Team, mortar 33
3x Brood Brother Heavy Weapons Team, mortar 33
Astra Militarum (outrider detachment)
HQ
Primaris Psyker, force stave 46
Fast Attack
3x Scout Sentinel, multilaser 105
3x Scout Sentinel, multilaser 105
3x Scout Sentinel, multilaser 105
3x Armoured Sentinel, plasmacannon 120
3x Armoured Sentinel, plasmacannon 120
3x Armoured Sentinel, plasmacannon 120
Heavy Support
Basilisk, heavy bolter 108
Basilisk, heavy bolter 108
total: 1748 pts
36 sentinels, 2 vehicles, 2 hwts, 2 characters
tactic: swarm the board with walkers while the psyker helps the basilisks and mortars. Meanwhile, the alphus snipes characters.
Obviously, this 8th edition list is inspired by 7th edition "emperors talon recon company" formation.
Given the size of sentinels, it's probably a pain to transport.
I don't have enough sentinel models to field even a fourth of the list.
Well, tbh, I probably won't be able to ever field this list.
Like dreadnought only lists, there's too much wounds concentrated on only a few models.
So, I wouldn't recommend anyone to actually build this.