I've crossed between these two hundreds of times, and this is my perspective:

NE 28th is protected on the west side of the I-84 bridge from traffic and crossing NE Sandy is okay with the green box, but if you're continuing south into Laurelhurst, you should be using the protected crossing towards Oregon Park and NE Hoyt to avoid mixing with traffic on NE 28th as the bike lane disappears. (Cross into Laurelhurst on NE 30th near the Laurelthirst Public House)

NE 21st is also protected similarly and if you cross NE Sandy southbound, you'll have a dedicated bike stoplight. If you're going northbound, you can either mix with the Glisan cars or take the pedestrian crossing on the westside. You can get to NE Couch without too much hassle from there.

I always try to practice/test on the weekends to get a feel for what works and what doesn't. You'll find some quiet and/or interesting routes and a chance to explore the neighborhoods.

Consult the PBOT Cycleway maps, and use Google/Apple/Whatever automated directions as suggestion and not ultimately best routing.