I don't recommend apps unless an actual problem is stated otherwise it's too often an XY problem with merchants self diagnosing AND self prescribing.
And even with a problem statement there are so many services/apps you can still end up needing to do the work of shortlist and testing a handful for the right feature fit; except for some rare niches with a singular app or clear winner. On top of all the existing recommendation seeking posts for most feature categories.
Translations and currency are operational needs.
cookies banners are regulatory requirements.
They have business reasons to even occupy mental space.
Translations is iffy for a new business as can you actually provide business support for customers of langauage-X..
All the things you mentioned are categories unto themselves that need to be researched separately.
Mainly apps should provide some metrics that prove it's helping some defined business goal. And apps should be a bad tradeoff in impacting website speed.
Email collection -
Most themes have a newsletter option, getting emails with a gamification app can be good way to increase bounce rates or have a big list of fake emails but you wont know until you spend time & money coming up with marketing campaigns and testing conversions. Use free apps to learn limits, klaviyo etc is expensive if you don't know the features you need or why.
badges and estimated delivery dates -
messaging is important but generally only something to action if customers are indicating they are confused about how your business operates because policies are not clear or findable.
Most themes have some sort of sale-badge feature, though to have configurable badges only some themes do that.
Cart upsell -
can't upsell if there's nothing in the cart to start with.
Use to increase AOV, but if you have no AOV an upsell app is probably wasting money.
UGC - aka social proof - aka constant maintenance moderation chore
If relying on word-of-mouth etc or are spending money brand building sure but you still either need a marketing plan or a killer product where users don't need any prompting. While keeping in mind UGC can be hard to proof as a conversion factor.
Good Hunting.
