Embed and document how work get prioritised:

Cost of Delay: what is the cost of having to wait

Cost of Delivery: what is the cost of implementing and delivering the work

Users can up/down-vote an item, which is an immediate input to increase, decrease, accelerate, stop the work on a certain item. It's not the only one though:

Value forecast: Short/long-term expectation of gains (incl. learning) and prevention of losses (incl. risks)

Cost estimate: Effort/cost of having/lacking experience/knowledge

Furthermore, priorization is done in every step on the Kanban, with more accurate information becoming available as more effort is put into forecasting and estimating.

Note: Compliance, regulatory, legal, corrective change (incidents with high severity) items bypass steps in the Delivery Kanban, consuming the capacity allocated to architecture and/or maintenance, yet this work still must be prioritised, which should be easier as they are often concrete in scope and time-lines, though estimating the effort most likely is the biggest unknown, yet time pressure and discipline in following the Readiness and Success Criteria should prevent gold-plating or cutting corners. It's just more disruptive in time and therefore time should be spent in preventing this situations from happening at all or escalating, which is a long-term preventative measure to consider.