one method - try this [Announce] node-red-contrib-buffer-parser - V2.0.2
The buffer parser takes your array of data & turns it into named items of any format you need (float, signed integer, byte revered if necessary (often necessary with modbus))...
then you can access each named items value like this
then paste that into the dashboard items like this...
demo flow...
[{"id":"68dcb361.27d5bc","type":"buffer-parser","z":"284fa9c6.f473c6","name":"","data":"payload","dataType":"msg","specification":"spec","specificationType":"ui","items":[{"type":"int16be","name":"item1","offset":"0","length":"1","offsetbit":"0","mask":""},{"type":"int16be","name":"item2","offset":"2","length":"1","offsetbit":"0","mask":""},{"type":"int16be","name":"item3","offset":"4","length":"1","offsetbit":"0","mask":""},{"type":"int16be","name":"item4","offset":"6","length":"1","offsetbit":"0","mask":""},{"type":"int16be","name":"item5","offset":"8","length":"1","offsetbit":"0","mask":""}],"swap1":"","swap2":"","swap3":"","swap1Type":"swap","swap2Type":"swap","swap3Type":"swap","msgProperty":"payload","msgPropertyType":"str","resultType":"object","resultTypeType":"output","multipleResult":false,"setTopic":true,"x":700,"y":540,"wires":[["ad8c8500.89fdd8","801b9f08.c2dcd","fa47c578.c6fdd8"]]},{"id":"5ad37cbb.990974","type":"inject","z":"284fa9c6.f473c6","name":"fake data","topic":"fake data","payload":"[12345,543321,31314,44444,71111,15243,43434,999]","payloadType":"json","repeat":"","crontab":"","once":false,"onceDelay":0.1,"x":520,"y":540,"wires":[["68dcb361.27d5bc"]]},{"id":"ad8c8500.89fdd8","type":"debug","z":"284fa9c6.f473c6","name":"","active":true,"tosidebar":true,"console":false,"tostatus":false,"complete":"payload","targetType":"msg","x":870,"y":540,"wires":[]},{"id":"801b9f08.c2dcd","type":"ui_text","z":"284fa9c6.f473c6","group":"9ff3d14a.12719","order":0,"width":0,"height":0,"name":"","label":"text","format":"{{payload.item1.value}}","layout":"row-spread","x":830,"y":640,"wires":[]},{"id":"fa47c578.c6fdd8","type":"ui_text","z":"284fa9c6.f473c6","group":"9ff3d14a.12719","order":1,"width":0,"height":0,"name":"","label":"text","format":"{{msg.payload.item2.value}}","layout":"row-spread","x":830,"y":680,"wires":[]},{"id":"9ff3d14a.12719","type":"ui_group","z":"","name":"Default","tab":"93ef5e6b.7382d","order":1,"disp":true,"width":"6","collapse":false},{"id":"93ef5e6b.7382d","type":"ui_tab","z":"","name":"STUFF","icon":"dashboard","disabled":false,"hidden":false}]