My biased point of view.
Are we still calling Bitcoin just "digital gold"?
Bitcoin is more than been a digital gold since it covers more than gold like scarcity or an hedge during crisis.
It is a decentralized payment method and a proof that financial sovereignty is possible.
Not excluding it's flaws Or is it becoming something more like a global macroeconomic tool?
Indirectly but it's still Young not to mention has no central head.
Is Bitcoin's main role still store of value?
Bitcoin is first a decentralized P2P payment method. Store of value is just a side effect of its potential and hedge towards inflation.
- Can it evolve further into a mainstream payment network (with Lightning, etc)?
Yes. One thing that has never seized in Bitcoin is continuous development to cover it's flaws. No system is perfect.
And what would be the endpoint for BTC adoption, in that case? Everybody accepting it as an ultimate store of value?
No endpoint to its adoption is people finally accepting financial freedom.
I see more options there

As BTC, first and foremost, was intended as an alternative to the traditional systems.
And it still is. Can you tell me an alternative to traditional system if it's not Bitcoin?
There was gap in the market for those that wanted self custody and Bitcoin was a solution
And still is.