Unlike Duolingo, the Pearson Test of English (PTE) seems to have gained traction. However, this is not standard.
Most universities would list alternatives to test/proof of English they accept. Check on each universities or school or course page.
In Italy, the university can use its discretion in issuing the LoA (letter of acceptance) which is required for visa purposes.
By the way, you may need more of Italian than English. The following, among others, might become relevant: DITALS, CELI, CILS, DELI, DILI, DALU, PLIDA, CEDILS ...
Note that IELTS itself has a list of 'alternatives': Comparing IELTS to other tests
If you don't want to write an English test, you may consider 'evaluating' your English proficiency based on your previous UG degree. ECCTIS (formerly NARIC) offers the Visas and Nationality services for this.
Just to add for completeness, the various test bodies test/evaluate against the Common European Framework of Reference for Languages (CEFR).
Duolingo was well received during the COVID period. Whether it's still regarded, I do not know.
For the category of persons in questions, seeking university admissions overseas, in my view, IELTS and TOEFL, I don't think they are not affordable. Pegging validity at 2 yrs might be the concern. Perhaps, making the results valid for at least 5 yrs.