Applying for summer trainee jobs as graduate

I completed some months ago my PhD in biochemistry in Finland and am seeking advice on finding an industry R&D position. While I learned Finnish during my studies, my job search has been unsuccessful. I've applied to numerous positions but haven't received any interviews. I understand the current economic climate is challenging, and finding employment in Finland can be difficult. My former colleagues either pursued postdocs or found positions through networking and asvised me to apply even when companies aren't actively hiring. This approach hasn't worked for me.

My main question is about summer trainee positions. I'm hesitant to ask directly for fear of appearing opportunistic, but could these positions be a viable path to a permanent role? I understand they are typically intended for university students, but if they are open to all applicants, I would consider applying. Currently, the R&D positions I see advertised seem to require extensive industry experience, which I lack. Is applying for a summer trainee position a reasonable strategy for someone with a PhD to gain industry experience and potentially transition into a permanent role?