Natural ways to encourage confidence and relaxation in cats

Two of my cats have developed confidence issues and are now beating the Jesus out of each other. They are both neutered and Malice our biggest offender has never felt very chill around the other cats but this is a whole new level. After a vet visit to make sure they had a clean bill of health they have given us some chill pills for them. Very expensive chill pills. Looking around the internets I'm noticing there's a lot of herbal mixtures for calming them. Anyone have any home mixed concoctions or store bought ones they would recommend?

Ps, we are also adding more enrichment to relieve any built up energy, adding safe spots and cat shelves and finding more places to stuff litter boxes. We have plenty of space for each cat. technically all 5 of our cats could have there own bedroom if the humans moved out lol. They are strictly indoor. But any other suggestions are welcomed as well.

Homeopathic remedy called ,Rescue remedy comfort & reassure   works wonders.
Also CBD for animals work's just as well.
Homeopet Anxiety relief is also good.

We have eleven indoor Persian cats left now.
They have all been here 8-15 years together...   They still get weird sometimes and need a good calming down!
You'll notice all three items are on the counter ready to be squirted down any trouble making kittys mouth!
We also use them at bath time and on our #135 Mastiff Molly  who gets anxiety attacks when we  leave her.

We have a situation of trying to integrate a new feral cat with two previously-feral cats -- lots of bullying, stalking and attempts to drive each other out of the house. One thing that seems to be working is a "Feliway Multi-Cat Pheromone Disperser" available from Amazon and other outlets. It's a plug-in disperser similar to an air freshener that's claimed to mimic the pheromones put out by a mama cat when nursing kittens. It seems to actually work; the little beasts are much calmer and accepting of each other's space when it's plugged in.

We have five cats, four indoor only (all special needs) and one indoor/outdoor.

Zylkene (a high tryotphan milk extract from the vet) worked fine, but is expensive. We switched to Yucalm, which contains 62.5mg L-Tryptophan, 60mg GABA Fermentate Blend, 50mg L-Arginine, 30mg Fish Protein Hydrolysate, 15mg Lemon Balm, 3.36mg Vitamin B1, 3.2mg Vitamin B6, 3.15mg Niacinamide, 42mcg Folic Acid, 5.3mcg Vitamin B12. COMPOSITION Product from Lactobacillus species rich in protein* (15%), Fish Protein Hydrolysate* (9.4%), Lemon Balm Powder* (4.7%), Maltodextrin*, Phosphate Salts, Yeasts*, Salt*, Lupin Protein Meal*, Magnesium Stearate, Sunflower Oil*, Hydrolysed Soy*. *Natural ADDITIVES Nutritional Additives (per kg) L-Tryptophan 195755mg, L-Arginine 156604mg, Vitamin B1 (Thiamine Hydrochloride) 10524mg, Vitamin B6 (Pyridoxine Hydrochloride) 10085mg, Niacinamide 9866mg, Folic Acid 132mg, Vitamin B12 (Cyanocobalamin) 16mg. I think the Yucalm is more effective, but it takes regular daily dosing for about a week to see the effect.

Cats can also safely have valerian, and ours love a valerian spray. And we buy calming cat crunchy treats containing valerian, hops, and lemon balm. Valerian can have a stimulant affect for some cats. They get very excited for a while, then chill. If Malice enjoys catnip toys, that can promote calmer behavior, too.

We also use a Feliway pheronome diffuser, as our house is small, one is enough.

Homeopathic Staphysagria can be useful for cats who are either bullies, or behaving more aggressively/ spraying /territory marking because they're being bullied. It made a huge difference to stop one of our chronic sprayers, when nothing from the vet worked. If he starts again, three days of staphysagria on his food will stop it again for months.

We're in the UK, so product names for the commercial products may be difference elsewhere.