This is really annoying, losing so much weight and muscle. Trying all ratios

I am male and eating very strictly, mostly fat and red meat.

I have tried most ratios. I started out eating very lean and lost a lot of weight, down to 67–70 kg(147lbs), which is uncomfortable. With clothes on I look like a skinny twig, but without a shirt I look healthy and well defined, with visible muscle. Still, I am not buying new clothes. I want to be at least 75 kg or preferably 80g(176lbs). I used to be 75–82 kg when I was eating a clean, protein-heavy, carb-based diet. Back then I was bloated, and a lot of that weight was water, and I also had more health issues. I am 178 cm in height 5,10 so

Since then, I have experimented with many ratios. I went very high fat and ate to satiety. With a high-fat ratio, I naturally ended up eating twice a day, around noon and then dinner, with no snacking. The problem is that I cannot eat enough fat and moderate protein together. I can only eat enough fat if I drastically lower protein, which leads to muscle loss and a low total food intake, and that causes further weight loss.

I am constantly stuck between two issues, either I get very tired after meals, or I get loose stools if I try to eat more to gain weight. I weigh everything and actively try to dial in the right ratio, but it is still not working. It is getting really frustrating.

I have always been skinny with a fast metabolism but I want to be a higher healthier weight.

I also train with heavy kettlebells.