Glantz thoroughly examined actual STAVKA documents issued to military districts in 1941 (For his book he includes the plans for the Baltic Military District as an example). Not theoretical plans or notes, but what the STAVKA actually ordered. All of them were entirely defensive in nature, with offensives only to be carried out after the enemy had been halted in the operational depths. This had been Soviet policy since serious war planning began. It's almost certain that offensive action was discussed and theorized at some point; but all militaries develop contingency and theoretical exercises. As your link shows, the Red Army did study number of offensive options. But nothing more than that. For the Red Army planning and a firm operational concept were everything; thus the absence of any STAVKA directives, plans, etc beyond the formulative stages is damning evidence that a serious offensive was never considered.
Even if the Stalin did seriously wish to launch an offensive, Glantz shows that the Red Army was in such a dismal state in 1941 that an offensive would be impossible to consider. It was unable to engage in offense or defense, which the STAVKA was aware of and desperately trying to rectify when Germany invaded. I've already listed some statistics as an example.
Solonin and others rely mostly on circumstantial evidence, conjecture, and a few facts. Glantz's works make extensive use of actualy Soviet archival data, and is supported by a host of statistics and documents.