Getting really annoyed with my Fenix 5 now, trying to a LTHR test.

Hello everyone, I am using a Fenix 5 with attached Soft Strap HRM.

I went to RUN - > held down menu -> selected lactate threshold guided test -> pressed start (I know the hrm was connected as it wouldnt let me do it otherwise).

Anyway I started slowly jogging deliberately to keep my heart rate below 150. I was warming up for 20 minutes and got no prompts or anything to go into a heart rate zone or anything. I was so frustrated. I stopped it and went back in just as I thought 'Did I even select the test?', anyway I did it a second time and still got no prompts after some time.

Can anyone look at these and tell me what is going on?

I wonder if its because it didnt connect to GPS straight away. I am getting really annoyed with this actually because I spent nearly £400 on this watch and the GPS is just poop! Some of the fitbits which are a fraction of the price connect to GPS in seconds and are much more accurate (that is my opinion only, but also my experience). Its really frustrating when I walk out the house and have to stand around for 10 minutes waiting for my GPS to turn on. I live really near the city and wasnt exactly near any tall buildings.

Was this gps issue part of the problem?
Is it waiting for me to run 1 mile? or 15 minutes?
If my battery is on 20% does the GPS get worse? feels that way.

Any tips would be really appreciated.

RUN 1 : https://connect.garmin.com/modern/activity/2993728059 (The first 100-200 metres of this run are totally bogus, I was never where it said I was, and then it goes all over the place?! What is going on garmin this GPS is craaazy!!!!)
RUN 2: https://connect.garmin.com/modern/activity/2993766289