Ryzens are a dynamic cpu. Intels are static. With an intel it's all 1 speed until it overheats, throttles back or shuts down. Ryzens are different. At 60°C they'll start dropping VID and click speeds slightly on individual cores, that maintains the best level of performance and temps. As temps get higher, reaching towards 80ish°C, more cores will lower speeds and voltage.
So if you normally get 4.0GHz across most of the cores at 70°C, and then kick in some uber cooling or airflow that would drop the temps to 65°C, a Ryzen says 'hey, I've got room to improve' and will kick the cores speeds right back up to 4.2GHz and temps back to 70°.
So will extra fans help temps? Unknown if you are reaching best speeds/max voltages, then the extra airflow will stand a chance to lower temps. If your cores are lowered because of the temp, the extra airflow might provide enough to allow further performance, but not change the temps.
If there is no fans cooling the rest of the equipment & what normally happens after the first 6 months of an install with no fans temps start to rise even more, it is bad practise not to have at least 2 fans in the case intake/extraction & this is a must in "hot all the time" countries really or water cooling !
Also I also approve of using an aftermarket CPU cooler because the stock Ryzen coolers recycle the air more as they blow down & if you have no extraction fan fitted the warm air has no where to go. I choose a CPU cooler fan which directs the air to the rear of the case for extraction by the rear case fan, if fitted of course, you could let the air go through the PSU fan if the PSU is at the top of the case but you just adding more heat inside the PSU case.
Having rear extraction & aftermarket cooling also helps keep the VRM's cooler as you are getting fresh air flowing across them keeping you PC cool & quieter.