Divines only reroll value ranges within a given modfier tier. That +1 modifier is T5 and there is no roll range so divine would do nothing to that modifier. I’m not a crafter so I don’t know if there’s a way to do it, but if there is it would likely be expensive enough to warrant starting a craft on a completely different staff instead.

I noticed some Path of Exile keywords in this post:

• SSF - Solo Self-Found (Wiki)

^(I am a bot.) ^| ^(All acronyms) ^| ^(Suggest)

The tier of the modifier is too low, so if you divine it, it’ll just reroll the other modifier values on the item.

I have no idea if there is a reliable way to increase the tier, so I would recommend using a different item with a higher tier modifier. iirc ilvl 81 has an opportunity +6 or +7 to spell skills.

Not possible to increase the all physical spell levels mod, best bet would be find the essence that gives +5 level of all spell skills and try to annul (by gamble slamming or using suffix annul omens) the current +1 off so you can use the essence or just start a new craft completely and find a better base

https://poe2db.tw/Perfect_Essence_of_Sorcery#PerfectEssenceofSorceryCurrencyPerfectEssenceCaster

There is no way to change the tier. The only way to do it would be to chaos/anull/fracture it out. There are omens you can use to make it more likely to get either a prefix or a suffix. None of this is reccomended as it is still based on RNG and you’re more likely to take out the desireable modifiers as you are the undesireable ones. Then you’d have to get a higher lever of phsyical spell skills or use an expensive essence

TLDR - it’s better to craft from a base that already has the most desireable rare roll on it and multiple prefix and suffix open modifier slots still available.

Sadly the same mods with different tiers are essentially completely different modifiers. You have tier 5 and there is no way to reliably change it to tier 1.

In SSF the perfect essence of sorcery is your best bet. Or find a staff that already has a good tier of spell skills