I played both in the past, and not both the same time. I won on both, but that's not true for everyone.
We now have 6+Reserve / 45 for 1.25 euro / 1 combination.
We have 20 / 70 Keno, pick 10 for the highest jackpot of keno, 1 euro / 1 combination, sold by two combinations.
20/70 is daily and cheaper to play.
6+1/45 is drawn twice a week and more expensive.
Chances and costs versus payouts, I'd go for keno because of the costs in the first place.
Other ideas? Did you compare payouts, chances, balance and other?
Last 5/6 paid less than 300 euros for 1.25 euro / play and 6+ / 45;
while I had, many years ago, 5/6 and >1600 euros 6+/42 for 50 eurocents / 1 combination.
That made me think and years ago I calculated chances, costs and payouts. I could play and win, but quit for a long time for the raise of the combination cost. Pick 3 and keno stayed unchanged. Euromillions became more expensive, stars were added and payouts went worse for the player.
Blabla and snip! Making chicon au gratin with mashed potatoes. Eat first, think later. Drink water before thinking to beer or dirty water called coffee from Starbucks etc! Mind your health and budget!