Ciao ​@Rehman. I think it won't be a problem but if you can upload the track on Strava every day you can free the memory on the watch deleting the file on it. Just an idea 

If you’re worried about recording the whole thing at once - you can record day-by-day then combine the files into a single ride afterwards - e.g. Combine FIT, GPX, CSV or TCX files for Garmin or Strava. Merge Heart Rate Power and GPS - then do a manual GPX activity upload.

(and delete the day-by-day activities from Strava to avoid the duplicates!)

Thanks, Vincenzo. I prefer to keep the entire journey saved as one activity.

Your device may auto save after some time. An alternate idea for you: record each day as usual, make them private, and combine all of them with a third party tool such as fitfiletools or Gotoes.

Hopefully someone with the same watch can answer but if you can pause and resume the acitivity later then it should work, subject to whatever limits Samsung impose. Some reddit threads from a year ago say an activity is limited to 24 hours total duration in Samsung health, so this is another thing to look into.

If you have the option, this would work no problem at all on Garmin.

To be safe I think you will have to do an activity per day and join it later as mentioned above.