Best 3 season synthetic bag for a 6ft2 wannabe wildcamper

After the collective wisdom here.

Down is off the table for me. I have a feather allergy that has caused nosebleeds and breathing trouble. Some say down in a bag shouldn't trigger but at the price, it's not worth the risk, so I am going synthetic and I am at peace with the weight and pack size penalty. What I want now is the best synthetic bag for my needs.

What I need:

• Synthetic only
• 3 season, comfort rating 0 or below
• As light and packable as synthetic gets
• Long enough for 6ft2 (188cm), so a Long or Large im guessing
• side sleeper compatible

Uses: Mourne Mountains Northern Ireland, the West Highland Way, and next July, the Inca Trail where the high camps get cold

The Shortlist I am considering is Rab Radeon -6C, Mammut Comfort Fiber -5C, Nemo Soul 15/25

I've gone round these options so much I think I'm a roundabout. I'd love to hear anyones experiences.

Open to other suggestions if anyone has hands on experience, especially anything that fits 6ft2 without being a squeeze.

1. What is the current consensus for the best 3 season synthetic bag? Whatever the community keeps coming back to.
2. Of my three, is the Mammut too much bag to carry for multi day backpacking, or is it worth the extra weight?
3. Any that punch above their weight on packability, since that is synthetic's weak spot?
4. Insulation types worth caring about, PrimaLoft versus own brand fills, or is it not worth obsessing over?

Budget is flexible for the right bag

Cheers in advance.