That muddy fox looks a cheap starting point and as recommended needs a stronger wheel set. Also probably a good idea to put hydraulic brakes on, and that may or may not be possible/easy/difficult with that frame.
Then a crank or front wheel kit. Brighton Bikes have been recommended for fitting kits to bikes if you cannot do it yourself.
I am heavy, but still 90 kg lighter, and have a Haibike Yamaha Hardtail Yamaha, and on occasion put it under real stress off road, landing from down hill drop offs arpund 20mph where the whole bike is in the air, before landing lower down the slope.
The beauty of a hardtail is you can have a rack and panniers, very useful. A guy following once down a bumpy steep trail said it looked mad with the panniers flying around!
It has been ridden 50% off road for all its life and probably a bit more and is over 16,000 miles now.
All I did to accommodate my weight was to replace the back wheel with a much stronger one.
The first was an off the shelf mavic that lasted 10,000 miles and then I spoilt myself with a hand built one with a wide section tough tyre run tubeless which has been superb but cost quite a lot.
As a curve ball if you have the money haibike do an entry level full suspension bike with yamaha system that is the toughest crank drive set up. It would still cost a pound shy of £3,000, and you might still need to put a stronger back wheel in.
https://www.e-bikeshop.co.uk/products/electric-bike-haibike-full-seven-4-2021?variant=42482860458222
Or go cheap and hopefully cheerful with this old well built classic
https://www.ebay.co.uk/itm/185543225852?hash=item2b333cf1fc:g:DaoAAOSw5Zpi~kWk&amdata=enc:AQAHAAAAoJqqbCK6XZWcI9rS/caupLzamktoXhtOQ41gpJXxTRaZiUD4xkVP2BHk2ZkzTRwNECk0kerTKhq8mjEKktavANoWGkD1v5v6elecD/TijEMlfGtzPhSfTtCnvmCAHmfg4/ganpgBtVdSJSM7/JLSc3ZXNTELMpCDbwmy9OasfWI8FPoKBuh9pjDCWYtCJn1zi4A/lHkGtziYgrEVQqshXZM=|tkp:Bk9SR-yrsJrZYA
Then a crank or front wheel kit. Brighton Bikes have been recommended for fitting kits to bikes if you cannot do it yourself.
I am heavy, but still 90 kg lighter, and have a Haibike Yamaha Hardtail Yamaha, and on occasion put it under real stress off road, landing from down hill drop offs arpund 20mph where the whole bike is in the air, before landing lower down the slope.
The beauty of a hardtail is you can have a rack and panniers, very useful. A guy following once down a bumpy steep trail said it looked mad with the panniers flying around!
It has been ridden 50% off road for all its life and probably a bit more and is over 16,000 miles now.
All I did to accommodate my weight was to replace the back wheel with a much stronger one.
The first was an off the shelf mavic that lasted 10,000 miles and then I spoilt myself with a hand built one with a wide section tough tyre run tubeless which has been superb but cost quite a lot.
As a curve ball if you have the money haibike do an entry level full suspension bike with yamaha system that is the toughest crank drive set up. It would still cost a pound shy of £3,000, and you might still need to put a stronger back wheel in.
https://www.e-bikeshop.co.uk/products/electric-bike-haibike-full-seven-4-2021?variant=42482860458222
Or go cheap and hopefully cheerful with this old well built classic
https://www.ebay.co.uk/itm/185543225852?hash=item2b333cf1fc:g:DaoAAOSw5Zpi~kWk&amdata=enc:AQAHAAAAoJqqbCK6XZWcI9rS/caupLzamktoXhtOQ41gpJXxTRaZiUD4xkVP2BHk2ZkzTRwNECk0kerTKhq8mjEKktavANoWGkD1v5v6elecD/TijEMlfGtzPhSfTtCnvmCAHmfg4/ganpgBtVdSJSM7/JLSc3ZXNTELMpCDbwmy9OasfWI8FPoKBuh9pjDCWYtCJn1zi4A/lHkGtziYgrEVQqshXZM=|tkp:Bk9SR-yrsJrZYA