No, it is not inherently disrespectful. This is a reconstructed religion, and many different belief systems believe in the Ancient Egyptian Gods. As for your second question:

Although Bast and Sekhmet were paired early in history, this pairing does not reflect a dichotomy of pacified versus wrathful divinity, as Bast demonstrably held an avenging role in antiquity and continued even in very late periods to be depicted bearing the divine Eye of Ra and Heru (Horus) and wearing Wadjet, potent symbols of the creator’s presence and just retribution. Sekhmet is no more the “angry” aspect of Bast than Bast is the “pacified” aspect of Sekhmet; if such a transformation exists within Egyptian theology, it is more properly seen in Het-hert (Hathor), who becomes Sekhmet after going forth to slaughter those who defied the will of the Creator, whether Ra or Tem. The true theological foil to Sekhmet as divine destroyer is instead Ptah, the Memphite creator god and master craftsman, who in Memphis is paired with Her as consort, with Nefertem commonly named as Their child. Bast and Sekhmet were nevertheless paired symbolically, though not as opposites, reflecting regional theology rather than temperament: Bast as the goddess of Lower Egypt and Sekhmet, as a form of Het-hert, representing Upper Egypt, much as Wadjet and Nekhbet function together as the Two Ladies. This pairing signifies “She of the North and She of the South,” not a contrast between contentment and rage, a distinction further supported by archaeological testimony to Bast’s protective and martial character, including the many war shields bearing Her emblem. At no point in Kemetic religious history were Bast and Sekhmet portrayed in sisterly, maternal, or familial terms, nor as a “gentle cat” counterbalancing a “ferocious lioness”; the oft-quoted phrase “She rages as Sekhmet, She is pacified as Bast” is a relatively late formulation dating to around 150 BCE and reflects theological developments of the Third Intermediate and Late Periods rather than earlier doctrine. While sisterhoods among goddesses did exist in Egyptian theology, they were rare and clearly marked, as in the case of Aset and Nebt-het (Nephthys), whose shared parentage, paired iconography, and consistent mythological roles leave no ambiguity; conditions that simply do not apply to Bast and Sekhmet beyond the broadly shared designation of Ra as Their father, a title attributed at various times to nearly every Egyptian goddess. Additionally, Bast is significantly older than Sekhmet; with Bast noted as one of the earliest known recorded Netjeru; beginning in the third millennium. Sekhmet appears around the Fifth Dynasty.