Capfriendly has something called Armchair GM:
Armchair-GM - CapFriendly - NHL Salary Caps
If you prefer doing it by spreadsheet, there is nothing wrong with that. The Armchair GM calculator does make it a bit easier.
If we assume Kelly gets a six figure extension, and Pinto gets his rumoured ask of 2.5M, we have about 8.5M in cap space with a 20 player roster.
That is without qualifying Brannstrom, or signing Kubalik or Tarasenko.
-Tarasenko might cost 6M-7M to extend.
-I would say close to zero chance Kubalik stays. If he is good, he prices himself out of Ottawa if Tarasenko stays. If he is just okay or bad for the rest of the season, he will want a change of scenery.
-I doubt they qualify Brannstrom due to the risk of an arbitration ruling they cannot walk away from. If they do extend him, I don't think he comes in much higher than he is now.
-If Sogaard will sign a 2 year 1M type contract, they could buyout Forsberg and they would save close to 1M in cap for 24-25 at the expense of losing about 1M in cap for 25-26. It would be close to cap neutral, just spread over 2 years. They could also shop him with retention. Forsberg at 1.375M x 1 year should be desirable. In that scenario, if Sogaard is ready and will sign a 2-3 year contract, anything under 1.375M would be cap neutral since Forsberg's retention would be a sunk cost.
The biggest need is a top 4 RHD and a right-handed middle 6 forward to replace Tarasenko (assuming the doesn't sign).
The above is the crop of UFA RHD that as of now will be available this offseason. Keep in mind, a lot of these players will be re-signed and won't make it to free agency.
When you look at that list, it makes it seem very unlikely that we will find a RHD via free agency. Once players re-sign with their current teams, or with teams they end up traded to, there will be very few legitimate top 4 options. Ottawa also into a top free agency destination.
If we want someone like Tanev or Pesce, we probably need to trade for them now and hope they will stay.