Learning Vs. Maintaining Languages as a Polyglot

Hi!

I’m looking for advice from experienced polyglots who have dealt with the dilemma of learning new languages while maintaining the ones you already have.

Right now I have approximately the following levels: English C2, Swedish C2, Arabic C1, French B2 and Persian B1.

I’m comfortable with letting my English, Swedish and Arabic be as they are. But until the end of the year I’m spending most of my time and energy (about 10-15 hours a week) on making sure my French is a solid B2 in all aspects while spending about 2 hours on Persian every week.

Now the issue is that I want to learn Spanish and Italian, as well as slowly improving my Persian eventually to a B2. Ideally I’d spend the entirety 2027 focusing on Spanish and 2028 focusing on Italian. My goal is really to be comfortable enough in these two languages so that I can use them while travelling and for day-to-day conversations. Ideally I’d internalize to a degree where I can let them rest dormant for long periods of time but being able to quickly get back into speaking them with minimal effort (much likely my Arabic).

But then the risk for cross contamination is rather high between Spanish and Italian and I’m unsure whether it’s worth it trying to maintain my French throughout all of this or if I should let it be dormant.

Right now I’m toying with the idea of doing Spanish 80%, French 10% and Persian 10% during 2027. Then having Italian at 60%, Spanish at 30% and Persian at 10% during 2028 and gradually decreasing my studies in Spanish.

How would you approach this? Keep in mind that 15 hours is probably my absolute max I can spend on language learning every week as I have a job and other duties. I’m trying to keep 7 hours a week my minimal amount of study time.

Thanks in advance
(TL)