Don't give your interviewer any ammunition that they can use to discriminate against you. It's illegal in many locales to discriminate based on a medical condition that doesn't directly impact your ability to do the job. People may still discriminate against you subconsciously, though, so it's best if you don't talk about it at all. For the most part, it shouldn't even be relevant.
Interviewers notice that most of the things listed on my resume
are from freshman or senior year
I think your resume is too itemized. Which year something happened isn't really important, as two people at the same university can take courses in a different order and get the same education. It's simpler to simply say that you were at university for years X-Y, and then give a list of relevant courses and accomplishments. Interviewers read a lot of resumes, so keep it short and focused.
and often also notice the slight reduction in GPA over the years
This is perfectly normal. Courses get harder as you go, so changes in GPA are not at all unusual. I know my own GPA was all over the place from one semester to the next. Most employers won't look at your transcript in that much detail, though. They might look at your overall GPA, plus your grades in one or two specific courses that are relevant to the job.
You mentioned that the underlying cause of the issue was the pandemic. If your academic "low" period corresponds to that particular time in history, I doubt anybody will bat an eye. That's when students were suddenly forced to attend class remotely, instructors had to figure out how to re-structure their courses for remote instruction on short notice, etc. It was a rough time for students and educators alike, and nobody was performing at normal levels during that time. I'd be willing to bet almost every recent graduate's resume would show interesting group projects and internships in 2019, and then none in 2020-21. If asked about it, "that's when the pandemic hit and we all went remote" would be an accurate and perfectly adequate answer. As an interviewer, I'd be a lot more suspicious if a student tried to claim that they did have extracurriculars, group projects, etc during that time.