Witches VS Patriarchy

I mean, to start with, throwing out a claim like that with no sources to back you up is not exactly arguing in good faith. It takes a lot more work to deny something when you're provided with exactly zero context on where or when this might be true (and it certainly isn't true in all countries at all times based on the data we have available).

There are some studies which suggest that lesbian couples do have a higher rate of domestic abuse. The CDC 2010 National Intimate Partner and Sexual Violence Survey (NISVS), for example reported that:

Four in 10 lesbian women (43.8%), 6 in 10 bisexual women (61.1%), and 1 in 3 heterosexual women (35.0%) reported experiencing rape, physical violence, and/or stalking within the context of an intimate partner relationship at least once during their lifetime (Table 3). This translates to an estimated 714,000 lesbian women, 2 million bisexual women, and 38.3 million heterosexual women in the United States. Bisexual women experienced significantly higher prevalence of these types of violence compared to lesbian and heterosexual women. (p. 18)

But it concluded that:

There were no statistically significant differences between the of rape, physical violence, and/or stalking when comparing lesbian women and heterosexual women.

This comes down to the fact that, as other commentors have alluded to, there are far fewer women overall in lesbian relationships compared with those in same-sex relationships. Even if the proportion of those suffering domestic abuse is slightly higher in lesbian relationships, there are far more women being abused in heterosexual relationships.

On top of this, it's important to remember that this percentage is from one survey undertaken in one country, and the reports that exist on lesbian spousal domestic abuse have statistics that vary wildly. The Wikipedia page on lesbian domestic abuse has a good summary of other difficulties in getting a clear picture of its prevalence:

Literature and research regarding domestic violence in lesbian relationships is relatively limited, including in the United States, United Kingdom, and Australia. Many different factors play into this, such as "different definitions of domestic violence, non-random, self-selected and opportunistic sampling methods (often organisation or agency based, or advertising for participants who have experienced violence) and different methods and types of data collected". This causes results to be unreliable, thus making it difficult to make general assumptions about the rates of lesbian domestic violence. This has caused rates of violence in lesbian relationships to range from 17 to 73 percent as of the 1990s, being too large of a scale to accurately determine the pervasiveness of lesbian abuse in the community.

With regards to homicide, there is again the issue of when/where, plus the lack of detailed statistics. But the chapter on Intimate Partner Homicide in the Routledge Handbook of Homicide Studies (available to download here suggests that the rate of lesbian spousal homicides is in fact the lowest compared to those in heterosexual and gay male relationships:

Available statistics suggests that the rate of IPH [Intimate Partner Homicide] is the lowest in lesbian couples compared to IPH rates in gay and heterosexual couples (Gannoni & Cussen, 2014; Mize & Shackelford, 2008; Statistics Canada, 2019). (p. 179)

That's honestly all I have time to write right now. But in conclusion, no, what you're stating here isn't true, not at all.