What are the options for obtaining a work permit in Thailand while on a Non-O marriage visa?

It doesn't matter if you are on a marriage visa extension, or a type B work visa, the requirements are the same, with the same requirements to get a work permit. The only time having a marriage extension makes a difference is if you open a business with your wife, not working for a difference company. The four Thai employees for each work permit isn't the only requirement. The company must also have bt2million in registered capital for each work permit. When your company says they reached their quota, then that usually means not enough registered capital for another work permit, so you are out of luck, and it doesn't matter if you are on a marriage visa, or a type B visa, the requirements are the same, and, you can not work at all without a work permit, not even while waiting for it to be approved. If your company is BOI registered then the four Thai employees isn't required, but the bt2million in registered capital is for each work permit. Again, it makes no difference whether you are married, or not, when working for a company not owned by you and your wife. The work permit requirements are the same. There is no need for the documents for a type B visa extension, but that is the only difference. You still must have a work permit, and they are saying they can't meet the requirements for another work permit.

You can't apply for your work permit yourself unless you set up a company. If you still work for the company they will have to apply for it .. and the permit belongs to the company .. they will also have to prove paid up capital.. I think now its over £100k or 00 million baht per foreign worker.. 🤔

I think you're going to struggle if you don't qualify for the LTR visa. The alternative is for your company to set up a subsidiary in Thailand and for you to be employed by that. Can't see you getting a work permit other than that short of setting up your own company and employing 4 Thai workers

You can apply for a work permit and work legally with the Non Imm O visa based on marriage, there's no requirement to wait for the 1 year extention of stay.

If their quota is full then there's not much you can do. They need to employ 4 thais for every 1 forigner. Only way to hire another foreigner is to hire 4 more thais.

Will you be doing actual work with Thailand? As in doing work with Thai companies and Thai customers? Or will you be doing remote work?

If you'll be doing remote work then you should see if you qualify for the "remote worker of foreign company" LTR visa.

If you'll be doing actual work in Thailand and not remotely, the only way you can do this is to be sponsored for a work permit by your company. You cannot apply for a work permit yourself, your company has to sponsor you and provide the paperwork to do so.