Usually people check mempool size and distribution of transaction fee rate for transaction in the mempool, but usually it's easier to use blockchain explorer (such as blockchair.com which shown by @Bitcoin_Arena) or bitcoin fees website to see the rough estimation.
BTW, it doesn't matter if there are too many inputs, you don't need to split it, the prioritization always will be based from the fee rate.
In fact, splitting one transaction into multiple transaction require you to spend more bitcoin on transaction fee (assuming all transaction uses same transaction fee rate)