Hello, So my team is using monday.com in a way that maybe helpful or easy modified to fit what you are looking for. Recently we noticed a big time waste in having our sales reps leave monday.com to send invoices check payments ETC. With the help of freshbooks API we are now able to send invoices (One time and automatic monthly) that all ties back to our product board to generate prices, descriptions ETC.
With this connection to freshbooks we are also able to quickly track our expense and payments to invoices and record them back into monday.com . Over all I really recommend finding a program that will link your bank and payment gateway together and provide a webhook ETC to utilize. Freshbooks is really great for us due to the pricing.
Hope this helps a bit and you can keep your eye out in the monday.com forums for this integration as an app my team is working on it.