Slow spreadsheet - need troubleshooting

Hi, I have a spreadsheet that has two tabs, one is essentially the original data which is YTD driven for a particular GL account, the company has smaller amounts of transactions, so by December we are talking about maybe 3-5k rows of transactions for the account total.

The main tab being utilized, has about 30 columns of look up and sumifs formulas referencing the source data and in total approx maybe 500 rows by year end? To me it doesn’t seem excessive. I’ve dealt with way heavier spreadsheets that have more omph and run faster. But for some reason this one is slow as all hell to work in. I’ve even tried barcoded some data and not seen any improvement.

I’m not too techy into what else could be slowing it down. And ideas on what to troubleshoot from here?