Visiting my boyfriend in UK, how to strengthen my application.

I'm planning to visit my boyfriend in the UK around January to February, and I'm trying to prepare everything I need for the visa application. I'm a Middle Eastern national currently living in a GCC country, which I’ve heard could be helpful in the process.

So far, I’m planning to submit the following documents:

A bank statement showing the buildup of my savings over time, with a balance atleast around £5,000.

A letter from my employer detailing my basic salary, any additional income, and confirmation that my accommodation is covered.

Proof that I live with my brother and that I help care for my two half sisters, which shows strong ties to my current country of residence.

A hotel reservation, global travel insurance, and a return flight ticket.

My current passport with previous travel stamps. However, one of my old passports is missing, and I’m not sure if that might be an issue.

Is there anything else I can provide or do to strengthen my visa application further?