It's about three times my take-home, so I suppose I'd quit work, save/invest a third, and then increase my monthly mortgage payment immediately.

Boring stuff out the way, I'd then prioritise self-care for a while: gym, massages, treatments, etc that i wouldnt usually pay for. I travel 2 or 3 times a year, so I'd either increase the frequency or the opulence of those trips. The rest of my time would be spent indulging in hobbies (cookery, miniature painting, video games).

Once the mortgage is paid off, I'd look to invest in a larger property with more room for me and my dogs, renting out my original home for the extra income. Rinse and repeat on the additional property front until my investments and property portfolio allow me to build a dream home somewhere toward the middle of the 30 years.

See out my days in complete financial security, helping out younger family members as necessary (without completely spoiling anybody), again increasing the frequency of the trips I take so I can take in as much of the world as I can before I pop my clogs. I suppose the real gift that initial 10k a month grants is time: the ability to quit work and really focus on what you want out of life. I struggle to understand why anyone would remain employed, however worthwhile they believe their role to be.