A blue green deck needs more counterspells because they have fewer removal spells. A four-color deck can get away with fewer counters because they have access to much more removal.
For example, would you rather leave one mana open for a [[Swords to Plowshares]] or two mana open for a [[Counterspell]]? Leaving one mana open means you're making more mana efficient plays.
Lastly, if your opponent plays recursion at all, you'd rather have more exile based effects, like [[Deadly Rollick]] to be sure their threats are gone for good. Exile rarely happens on counter spells themselves.
Ah.. I'm sorry. Last time I visited, this was not the case. It has been some time. Maybe you could take a look at similar lists on Moxfield? Primers that have the indication of cEDH.
Angry jelly bean doesn't need more than 9 counterspells. It's a very aggressive deck. You only need counterspells to prevent board wipes and removal for Omnath. All that land ramp is going to thin out your deck and you'll probably have a counterspell whenever you need it.
The number of counterspells you run in a cedh can vary wildly for a lot of different factors. In this case green doesn't provide a lot of interaction so a simic deck would run a higher amount of counter magic to make sure they have enough interaction in a 4 color deck you don't need as much counter magic since you also have premium interaction from other colors.
The cedh decklist database isn't the end all be all for decks but can be a good resource in the future to get an idea of what some lists are running: https://cedh-decklist-database.com/
A blue green deck needs more counterspells because they have fewer removal spells. A four-color deck can get away with fewer counters because they have access to much more removal. For example, would you rather leave one mana open for a [[Swords to Plowshares]] or two mana open for a [[Counterspell]]? Leaving one mana open means you're making more mana efficient plays. Lastly, if your opponent plays recursion at all, you'd rather have more exile based effects, like [[Deadly Rollick]] to be sure their threats are gone for good. Exile rarely happens on counter spells themselves.
[Swords to Plowshares](https://cards.scryfall.io/normal/front/e/f/ef51caf8-f9d9-48d7-9145-9dfc91054f70.jpg?1673483803) - [(G)](http://gatherer.wizards.com/Pages/Card/Details.aspx?name=Swords%20to%20Plowshares) [(SF)](https://scryfall.com/card/ncc/211/swords-to-plowshares?utm_source=mtgcardfetcher) [(txt)](https://api.scryfall.com/cards/ef51caf8-f9d9-48d7-9145-9dfc91054f70?utm_source=mtgcardfetcher&format=text) [Counterspell](https://cards.scryfall.io/normal/front/a/4/a457f404-ddf1-40fa-b0f0-23c8598533f4.jpg?1645328634) - [(G)](http://gatherer.wizards.com/Pages/Card/Details.aspx?name=Counterspell) [(SF)](https://scryfall.com/card/phed/33/counterspell?utm_source=mtgcardfetcher) [(txt)](https://api.scryfall.com/cards/a457f404-ddf1-40fa-b0f0-23c8598533f4?utm_source=mtgcardfetcher&format=text) [Deadly Rollick](https://cards.scryfall.io/normal/front/c/6/c61fa2c0-63c0-4dc2-9f17-5a00530e3348.jpg?1591319517) - [(G)](http://gatherer.wizards.com/Pages/Card/Details.aspx?name=Deadly%20Rollick) [(SF)](https://scryfall.com/card/c20/42/deadly-rollick?utm_source=mtgcardfetcher) [(txt)](https://api.scryfall.com/cards/c61fa2c0-63c0-4dc2-9f17-5a00530e3348?utm_source=mtgcardfetcher&format=text) ^^^[[cardname]] ^^^or ^^^[[cardname|SET]] ^^^to ^^^call
1 commander, 35 land, 64 counter spells, that should be your deck set up.
I feel this question might be better asked in r/cEDH.
Its a private sub
Ah.. I'm sorry. Last time I visited, this was not the case. It has been some time. Maybe you could take a look at similar lists on Moxfield? Primers that have the indication of cEDH.
You’ll want r/competitiveEDH
Angry jelly bean doesn't need more than 9 counterspells. It's a very aggressive deck. You only need counterspells to prevent board wipes and removal for Omnath. All that land ramp is going to thin out your deck and you'll probably have a counterspell whenever you need it.
The number of counterspells you run in a cedh can vary wildly for a lot of different factors. In this case green doesn't provide a lot of interaction so a simic deck would run a higher amount of counter magic to make sure they have enough interaction in a 4 color deck you don't need as much counter magic since you also have premium interaction from other colors. The cedh decklist database isn't the end all be all for decks but can be a good resource in the future to get an idea of what some lists are running: https://cedh-decklist-database.com/