Could it become another Lake Nyos?
If the CO2 is bubbling out (which it is) it isn’t building up, which is what happens in lakes like Nyos.
Interestingly, I went to go look at some academic papers on the eruption 12,000 years ago - the ash and pyroclastic flows temporarily damned the Rhine in two places, and would have completely flooded the city of Koblenz; and then after the dam broke a 30+foot wave went down the Rhine.