Nothing wrong with that / can't do much better, except for the obligatory vMA fire staff on the back bar and, if you're solo, possibly 1x Skoria instead of Slimecraw. The way to test this is on a normal dummy, albeit mob packs in arenas may only have 9.1K resistances. As long as you're under that, 1x penetration (Skoria) should beat 1x crit (Slimecraw).

I personally don't use a mythic on my PvE magplar, because even for solo arenas that class has enough self-healing. Keeps the build simple / not having to worry of Pale Order accidentally slotted in a group. My setup is:

1x-2x Med, 5x-6x light
Deadly front bar
Whorl of Depths (Ansuul should result in more self-healing and should be competitive)
Nerieneth, Zaan or Iceheart (I tried Velothi once, Nerieneth is at least as good)
Infused vMA fire staff back bar with berserker enchant

In vVH, for the Pyrelord, I might swap to something slightly tankier, however for the final boss I prefer full damage. I basically have some tankier options in my pocket for world bosses and the like, and for the Pyrelord fight.

Option 1 is a shielding setup, swapping Deadly out for Hexos Ward and using Iceheart. For historical reasons I use False God instead of Whorl on that build, but it's really a question of whether you need the extra sustain.

Option 2 is still light armor, but using Aetherial Ascension (both bars) and False God on the front bar. This is less damage than Option 1. It goes for high / near capped resistances, albeit still light armor for the crit / pen / sustain. It's basically just different, not necessarily tankier, but for some solo world boss fights it works better than the shielding setup.

Option 3 is the fake tank setup with a Tormentor back bar, False God front bar (I think), a monster set and a mythic. I have Explosive Charge on the back bar for the taunt. It's no longer an AOE taunt, but the heal and resistances from Tormentor made me hang on to this setup for now. The resistances carry to the front bar.

Infinite Archive is an entirely separate topic. You got to build for Focused Efforts by applying as many status effects as you can, preferably in AOE. You got to find a solution for the marauders. You probably want multiple gear setups in your inventory, otherwise it's just so slow at the beginning. Above all you must pay attention to detail, notably to your enchants. Dual-wield is highly recommended for enchant / status effect variety. A Weakening enchant on your other weapon will help with marauders. I am not 100% happy with my current setup, but here goes:

Unleashed Terror back bar, dual wield. Applies Hemorrhaging in AOE via Explosive Charge with high uptime. This set reprocs the status effect while it is active. Quick Cloak to keep activating the enchant. Front bar: Infused Lightning staff with a Weakening Enchant. Food: Health / dual-regen food. Mythic: Esoteric Greaves. This setup allows you to deal with marauders, even Gothmau, for at least a couple of arcs. I've been to the latter half of arc 5 with this (solo). What I'm not happy about is basically the damage in the early arcs / without Focused Efforts.

The remaining two sets are up for discussion. I've used Whorl + Zaan in early arcs, later Aetherial Ascenscion + Zaan, but .... eh. Zaan can proc Burning, but not sure. I've tried Alessia's Bulwark and Dragon's Appetite in the past, instead of Whorl, and I tried Sul-Xan on my Arcanist. The latter should be good for pure damage in the Archive, but you can may do best by also having a boss burn setup with Mech Acuity and Elf Bane, using the fire destro ult, and other speciality setups.

The word "small-scale" invokes PvP in my mind. Needless to say, that would be a whole other topic where everything discussed so far goes out the window. I don't PvP often with my magplar, but for what it's worth I use Rallying Cry (front bar), Wretched Vitality (back bar), Saint And Seducer, and Zoal in PvP.