Hi, Welcome along.
To answer your question re French lace.....I wear it and get many months wear from it ..in fact the hair will ` fail` before the lace does ! It`s robust. Of course, how you treat any system, will affect the serviceable - life of it.......swimming in sea water and / or chlorinated swimming pools, will have a negative effect...... you`d need to rinse the hair / lace immediately after swimming, with fresh clean water and use a leave-in conditioner to help the hair.. I`m against frequent shampooing, as regular readers will know ...using lots of styling products leads to build-up, and this needs to be shampooed out ...frequent shampooing will dry /damage the hair and lighten / ` lift` the color from it.....
Wetting the hair frequently is fine.....shampooing it isn`t . As you like to exercise, you`ll [naturally] sweat....you`ll need to keep your base ` clean` and remove sweat....the acids in sweat will weaken the lace, over time....it will also affect Polyurethane... I`ve worn Poly.-perimeter bases and exercised regularly...eventually you get pin-holes appearing in Poly and these then get bigger [ it does take quite a while though !] If you expose your system to sweat frequently, you`d be best to go for a more ` regular` removal and cleaning of your scalp and base fully, in the interests of hygiene and scalp-health...... I often apply some shampoo directly to the base itself ,when it`s wet, but avoid applying it directly to the hair.....
In my opinion [others may differ !] you`d be best to get a topper rather than a partial....the topper would be easier to work-with , taking your ` active` lifestyle into account .....it would ` hold` better to larger area than a partial would ....your thinning will carry on / progress , sadly , so if you deal with it now it will look less obvious in , say , twelve months time....you could simply get a light-density topper to begin with and increase the density on subsequent orders....that way , you won`t draw ` unwanted` attention from those who know you, and who you don`t wish to know you`re wearing.
Losing hair is not a pleasant experience...we`re all in the same boat....it comes with a lot of psychological issues / aspects ...we all put off the inevitable ` fact` that we`ll most likely end up wearing, until it becomes just a hobsons` choice.....go bald and accept it, or wear, and at least ` mask` the issue.....
Hope some of the above helps you make your decisions / choices !