FWIW, I typed in .MSFT220318C300+.MSFT220318P300 as the MSFT March '22 300 straddle and TDA's ThinkOrSwim happily charted that. I chart and trade the underlying (and options) and not sure what value is there in charting options legs, let alone a combo, but if it works for you...
Looks like this
View attachment 276890
Also, with TOS running
on a windows machine, in Excel =RTD("tos.rtd", , "VEGA",UPPER(".MSFT220318C300")) will give you the vega. No historical though. You can run a bunch of symbols this way and do real time analysis
https://www.lockeinyoursuccess.com/wp-content/uploads/2016/04/Connecting-ThinkOrSwim-to-Excel.pdf should give you list of everything possible from TOS