Can I apply for an eVisa to Thailand using a refundable hotel booking instead of an invitation letter from my fiancé?

Hi guys

I’m applying for evisa, so I have to book flights first yeah? My main question, I’m staying 50 nights, if I book hotel for say a week just to show booking confirmation will this do? I’ll be actually staying with my fiancé in Bangkok but problem is she’ll need to write a letter for me and too much hassle and she’s currently here in UK with me, I wanted to get the ball rolling so my question is will a refundable hotel booking be ok just in order to get through this visa? I don’t plan on going until mid December and i understand you have 90 days from the point of the visa been accepted which is useful, I’m naturally anxious so want to start the visa asap, appreciate any help on this, I understand I’ll have to book flights first but surely you don’t need to also show every single hotel booking as I say I’ll bd staying in my fiancés condo but we will be visiting 3/4 islands during my 7 week stay, thanks