Board advice for unfit, out of practice surfer!

Please could someone give me a few pointers on which board to choose!
About me: I have barely surfed in years and while I am confident I will pick it back up again quickly, I know I will struggle at first. I am a pretty chubby girl (5'4 and 95kg). I am normally around 82kg but I piled on the pounds in the first covid lockdown, then overdid it in the gym and injured myself so have been very inactive for a fair while.
My goals: I am about to undertake a bit of an adventure and spend 6 months living in a van while working as many hours as possible, to save enough money to get back to my family in Kenya. I am going to spend as much time as possible at the beach and surfing. If I have to be away from my home and family then I thought I would embrace a challenge and adventure, and pick back up a hobby I used to love. I want to make the most of this season to lose some weight and build my fitness and endurance.
The choices: I know you're all going to say nooooo but I am looking at either the Tahe Malibu 7'9" or the Tahe Magnum 8'4", which are £279/£319 respectively. I need a board that I won't get frustrated with and will progress quickly on. I originally learnt on a 7'3" bic popout when I was a teenager and it did me well. These are the options because... well, money basically. I've scoured secondhand listings and found nothing suitable for my budget. Really I don't want to spend more than £300 so I am looking to see if you think I will be ok on the 7'9" or will I struggle because of my size? By the time I buy a board bag and leash etc etc the £ really start to add up. The surfboard size guide on this site recommends over 7'10" boards and at least 3" thickness for someone my weight and the malibu is just shy of both of those. If I am surfing 3+ times a week (and losing weight hopefully quite quickly as I become considerably more active), will I be ok to choose the smaller board? It would also more easily fit in the van when I want to put it inside rather than on the roof.
I am probably really overthinking this but finances are so tight and I really want this to be an enjoyable 6 months of surfing rather than being frustrated and regretting my board choice. Thanks in advance for any insight!
About me: I have barely surfed in years and while I am confident I will pick it back up again quickly, I know I will struggle at first. I am a pretty chubby girl (5'4 and 95kg). I am normally around 82kg but I piled on the pounds in the first covid lockdown, then overdid it in the gym and injured myself so have been very inactive for a fair while.
My goals: I am about to undertake a bit of an adventure and spend 6 months living in a van while working as many hours as possible, to save enough money to get back to my family in Kenya. I am going to spend as much time as possible at the beach and surfing. If I have to be away from my home and family then I thought I would embrace a challenge and adventure, and pick back up a hobby I used to love. I want to make the most of this season to lose some weight and build my fitness and endurance.
The choices: I know you're all going to say nooooo but I am looking at either the Tahe Malibu 7'9" or the Tahe Magnum 8'4", which are £279/£319 respectively. I need a board that I won't get frustrated with and will progress quickly on. I originally learnt on a 7'3" bic popout when I was a teenager and it did me well. These are the options because... well, money basically. I've scoured secondhand listings and found nothing suitable for my budget. Really I don't want to spend more than £300 so I am looking to see if you think I will be ok on the 7'9" or will I struggle because of my size? By the time I buy a board bag and leash etc etc the £ really start to add up. The surfboard size guide on this site recommends over 7'10" boards and at least 3" thickness for someone my weight and the malibu is just shy of both of those. If I am surfing 3+ times a week (and losing weight hopefully quite quickly as I become considerably more active), will I be ok to choose the smaller board? It would also more easily fit in the van when I want to put it inside rather than on the roof.
I am probably really overthinking this but finances are so tight and I really want this to be an enjoyable 6 months of surfing rather than being frustrated and regretting my board choice. Thanks in advance for any insight!