Can you change airways when they cross without a named fix? There are a few victor airways that cross without a named fix, just two solid lines drawn over each other on the IFR low charts. Can these be used as intersections for changing airways in IFR route planning? Assuming you are above MEA for both, prior to the crossing. They aren't very common but I happen to have one very near my usual airport that along with a poor DP makes planning for certain directions rather tedious.
Examples

the crossing of V55 and V170 just north of JMS VOR on chart enroute L-14 North Dakota;
V495 and V23 with V187 over Tacoma(this one may be due to SEA class B) ;
V183 NE of RZS near Santa Barbra, could you plan to turn north from V183 onto V485 or V107?
Yes one can fly one airway to intercept another. Many reasons exist as to why not all intersecting airways have an intersection, the simplest being, it wasn't necessary.
I will suspect one may encounter difficulties in executing your desire to change airways as stated. Such would be the inability to file a flight plan with dispatch or that flight planning software can't/won't accept this unconventional navigation method and the most illogical, if one could accomplish the later, I would image would be ATC. Why? Because the controller has never encountered this situation, before and doesn't want to explain their actions should something go afoul.
For years ATC would issue preferential routes to aircraft departing KPIA to KORD as such; PIA PIA030R V10 PLANO ORD. Aircraft would depart KPIA on the tower assigned departure heading then be vectored to join the PIA 030-radial to intercept Victor-10 northeast of BDF VOR onward to KORD. Then computers became more involved along with flight management systems and pilots were no longer capable to navigate this route because computers couldn't calculate the routing or how to intercept one radial (airway) from another without a set point (intersection) along the second radial , something pilots had done since the 1950's.