the OP's query: booking.com and apply some filter options. Low budget chains like Ibis should be entirely okay.

OP: your budget is unrealistically low for what you want

Did a quick booking search and the only thing that seems to tick most of your boxes, on that budget is:

https://www.booking.com/hotel/nl/ibi...ighlight_room=

Well outside the centre of town. If you want to be more central, you'll have to pay more.

This would be my choice, mostly because of easy transport options (tramstops to big museums and city centre). The are is well-heeled and genteel, but it isn't in the centre of town (nor does it have to be, since public transport is so excellent) Be aware that being pregnant you can claim assigned seats, usually at the front of the tram.

https://www.booking.com/hotel/nl/bee...rc=hp_iw_title