NSA starting difficulties - MHR and LTHR

Hello all. Last week I got introduced to NSA but I am having some starting difficulties with my MHR and LTHR.

About me: I am 36 yo male with two young kids. Started running in beginning May this year. At the end of May I did a solo 5k time trial at 22:39. Started following some Jack Daniels kind of program and ran 4 times a week. Raced 10k on August 23rd at 46:04 (heavy wind that day) and 5k on August 28th at 20:59. I consider my max heart rate being 194 (highest recorded heart rate since I got Garmin FR 165 in July) and reached 194 in both my 10k and 5k race.

When I put my 5k race time of 20:59 into lactrace calculator it gives me my easy and sub-T paces. My difficulties lie in that I believe that my max heart rate is higher and that I don't know my lactate threshold heart rate.

- Easy runs: Lactrace suggest easy pace being 6:12/km. I've gone on 3 easy runs now and when I try to stay under 70% MHR (136 HR for me) I am running close to 7:00/km.

- LTHR: I just signed up to intervals.icu and it suggests that my Threshold HR is 176. Looking over my activities it has suggested that I raise my Threshold HR on three occasions. First from a workout of 8 x 1km at 4:30/km (1 min) on August 16 "Threshold HR +3 to 179 bpm from 98% of 20m at 183 bpm". And the second and third time from my 10k race ("Threshold HR +9 to 185 bpm from 98% of 20m at 189 bpm") and 5k race ("Threshold HR +7 to 183 bpm from 98% of 20m at 187 bpm") (yeah I know what sirpoc said about LTHR from races on page 17 of the letsrun thread). Is my only option to do a 30 min Friel test?