Using Picture-In-Picture for two GoPros. Way to make the transition seamless between clips?

I'm a novice moto-vlogger. I have two GoPro Cameras I use on most rides and sometimes also some Insta360 footage. I have a GoPro on my helmet facing forward and another GoPro on my handlebars facing me with some footage to the rear.

I am using iMovie to compile and edit the clips. I use the picture in picture feature to have the main view be me looking forward and the handlebar view in the smaller picture in a corner.

GoPro splits all their clips up into like 5 minute increments. Compiling the video for say a 30 minute ride, and editing the footage I actually want to use, becomes this exercise with me coordinating the footage and editing it down. One of the things I'm running into is that where GoPro cuts the footage, I have to keep adding a Picture in Picture feature each time I add another 5 minute increment. The picture size is different sometimes if I don't get it just right and the Picture in Picture goes away for a split second or so and then re-appears. I've seen the little timing "drag" things and I drag both of them to Zero for the picture going out and the new clip coming in. It still blips.

The main GoPro is seamless and doesn't do this little blip out, only the Picture in Picture. Is there a way to make the Picture in Picture be seamless instead of blipping in and out?

Is there a better way to go about me doing this process so the Picture in Picture doesn't have to be selected each time I drag in new clips?

Thank you.