Changing url slugs after copying pages to second language

I am copy my English language pages to the second language on our web page which is Polish.

I am not using automatic translation as our site uses very specific scientific language and lot of the content includes images with text explanations embedded in the .jpg images. Also anyone who is interested in what we have offer is mostly experienced scientist who will speak English.

My question about changing the url and slug from English to Polish. For example:
On the English side megantech/en/graphene/carbon-materials

When I copy this page to the Polish side I get
megantech/pl/graphene/carbon-materials

I then change the titles the pages
graphene → grafen
carbon-materials → Materiały węglowe

I can change the titles of the pages by using the attribute tab in the sitemap section of the dashboard. But in this section I cannot change the url slugs.

I can change the url slugs the Page Setting Tab in the sub tabs “SEO” and “Location” then I get
megantech/pl/grafen/Materiały-węglowe

I have 2 questions:
Is there a quicker way to change the url slugs than using the Page Setting Tab and the sub tabs “SEO” and “Location” ?

The second question is worth to change the url slugs ??
With our existing website if I google “graphene/carbon-materials” we are no where to be seen on the first pages of the results
If I google “grafen/Materiały-węglowe” we get much better rankings with some of our Polish terms we get to the top of the first page.
So I have always assume that the url slugs are very important for the search engines.
However I recently read that with the coming of AI SEO criteria will become less important.

Does anyone have any comments and advice on this subject ?

1st question: do it in the sitemap it’s much quicker than in the pages, unless you do it on newly created pages (for that it may be interesting to develop some special script)
2nd question… no advice: search engines always mistake or even lie on their future! in the meanwhile, I think you’re doing a good job translating urls, even it it takes time